Obesity and Diet 4

Diet has bigger impact on emotional well-being in women than in men

August 27, 2018

Science Daily/Binghamton University

Women may need a more nutrient-rich diet to support a positive emotional well-being, according to new research.

 

Mounting evidence suggests that anatomical and functional differences in men's and women's brain dictate susceptibility to mental disease. However, little is known about the role of dietary patterns in gender-specific psychological wellbeing. A team of researchers led by Lina Begdache, assistant professor of health and wellness studies at Binghamton University, conducted an anonymous survey of 563 participants (48 percent men and 52 percent women) through social media to investigate this issue. Begdache and her team found that men are more likely to experience mental well-being until nutritional deficiencies arise. Women, however, are less likely to experience mental well-being until a balanced diet and a healthy lifestyle are followed.

 

According to Begdache, these results may explain reports from previous studies that show that women are at a greater risk for mental distress when compared to men, and emphasize the role of a nutrient-dense diet in mental wellbeing.

 

"The biggest takeaway is that women may need a larger spectrum of nutrients to support mood, compared to men," said Begdache. "These findings may explain the reason why women are twice more likely to be diagnosed with anxiety and depression and suffer from longer episodes, compared to men. Today's diet is high in energy but poor in key nutrients that support brain anatomy and functionality."

 

Evidence suggests that our ancestors' diet, which was a high-energy-nutrient-dense diet, contributed significantly to brain volumes and cognitive evolution of humankind, said Begdache.

 

"Males and females had different physical and emotional responsibilities that may have necessitated different energy requirements and food preference," she said. "Thus, gender-based differential food and energy intake may explain the differential brain volumes and connectivity between females and males. Therefore, a potential mismatch is happening between our contemporary diet and the evolved human brain which is disturbing the normal functionality of certain systems in the brain.

https://www.sciencedaily.com/releases/2018/08/180827080914.htm

Teenagers can thank their parents' positive attitude for avoiding obesity

July 9, 2018

Science Daily/University of Bristol

Teenagers are less likely to be overweight if their mum or dad had a positive attitude during pregnancy, a new study finds.

 

Using answers from more than 7000 parents who took part in the Children of the 90s longitudinal study about their personality, mood and attitude during pregnancy; similar answers from their children at age of eight and the child's fat mass measurement up to the age of 17, researchers have assessed that a mother's psychological background during pregnancy is a factor associated with teenage weight gain.

 

The study examines a largely uncharted personality attribute known as the Locus of Control. It is a psychological measure for an individual's attitudes towards their lifestyle and a belief in being able to change outcomes, such as health, through their own actions. Someone with an external Locus of Control would feel that there is little point in making an effort as what happens to them is down to luck and circumstance.

 

Researchers found that teenagers at age 15 had an excess weight of actual fat in their body of 1.7kg if their mothers did not think their actions would make a difference and held a laissez-faire attitude. If their fathers had this attitude the excess weight of fat was 1.49kg and if the child thought this way the excess was 1.5kg.

 

Lead author and founder of the Children of the 90s study Professor Jean Golding said: "Although we know that poor diet and lack of exercise are partly responsible for increasing obesity in both adults and children in the developed world, there is little research into the contribution of psychological factors behind excessive weight gain.

 

"Thanks to the questionnaires and body measurements available through the Children of the 90s study we've been able to show that a lack of self-belief in a parent's ability to influence change by healthy eating, stopping smoking or breast feeding is a contributing factor to their child being overweight by the time they are 15.

 

"This is important research for health campaigners looking to change behaviours and the next steps should be looking at the differences between parents who managed to change their Locus of Control compared to those who did not change."

 

Candler Professor of Psychology Stephen Nowicki at Emory University, Atlanta contributed to the study and added "We see this as an initial step in understanding the complex effects of parents' locus of control on their children's ability to develop a healthy style during the, at times tumultuous teen age years.

https://www.sciencedaily.com/releases/2018/07/180709120159.htm

Evening preference, lack of sleep associated with higher BMI in people with prediabetes

August 15, 2018

Science Daily/University of Illinois at Chicago

People with prediabetes who go to bed later, eat meals later and are more active and alert later in the day -- those who have an 'evening preference' -- have higher body mass indices compared with people with prediabetes who do things earlier in the day, or exhibit morning preference.

 

The results of the study -- which looked at Asian participants and was led by Dr. Sirimon Reutrakul, associate professor of endocrinology, diabetes and metabolism in the UIC College of Medicine -- are published in the journal Frontiers in Endocrinology.

 

Prediabetes is a condition where blood sugar levels are higher than normal but not yet high enough to be Type 2 diabetes. Without modifications to diet and exercise, patients with prediabetes have a very high risk of developing Type 2 diabetes.

 

Lack of sufficient sleep has been previously linked to an increased risk for numerous health conditions, including obesity and diabetes. Evening preference has also been linked to higher weight and higher risk for diabetes.

 

Reutrakul and her colleagues wanted to investigate the relationship between morning/evening preference and BMI -- a measure of body fat in relation to height and weight -- among people with prediabetes.

 

"Diabetes is such a widespread disease with such an impact on quality of life, that identifying new lifestyle factors that might play into its development can help us advise patients with an early stage of the disease on things they can do to turn it around and prevent prediabetes from becoming full-blown diabetes," said Reutrakul.

 

A total of 2,133 participants with prediabetes enrolled in the study. Their morning/evening preference was assessed through a questionnaire.

 

Participants who scored high in "morningness" answered questions indicating that they preferred to wake up earlier, have activities earlier, and felt more alert earlier in the day compared with those who scored high on "eveningness." Sleep duration and timing were obtained using a questionnaire and the extent of social jet lag was evaluated for each participant. Social jet lag reflects a shift in sleep timing between weekdays and weekends. Greater social jetlag (e.g., larger shift in sleep timing) has previously been shown to be associated with higher BMI in some populations. The average age of the participants was 64 years old, and the average BMI was 25.8 kilograms per meter squared. Average sleep duration was about seven hours per night.

 

The researchers found that for participants younger than 60 years of age, higher levels of social jet lag were associated with a higher BMI. Among participants older than 60 years old, those with more evening preference had higher BMIs and this effect was partly due to having insufficient sleep but not social jet lag. Evening preference was directly associated with higher BMI in this group.

 

"Timing and duration of sleep are potentially modifiable," said Reutrakul. "People can have more regular bedtimes and aim to have more sleep, which may help reduce BMI and the potential development of diabetes in this high-risk group."

https://www.sciencedaily.com/releases/2018/08/180815141422.htm

Adequate Sleep Helps Weight Loss

September 17, 2012

Science Daily/Canadian Medical Association Journal

Adequate sleep is an important part of a weight loss plan and should be added to the recommended mix of diet and exercise, states a commentary in CMAJ (Canadian Medical Association Journal).

 

Although calorie restriction and increased physical activity are recommended for weight loss, there is significant evidence that inadequate sleep is contributing to obesity. Lack of sleep increases the stimulus to consume more food and increases appetite-regulating hormones. “Sleep should be included as part of the lifestyle package that traditionally has focused on diet and physical activity."

 

"The solution [to weight loss] is not as simple as 'eat less, move more, sleep more,'" write Drs. Jean-Phillippe Chaput, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario and Angelo Tremblay, Laval University, Québec, Quebec.

 

"However, an accumulating body of evidence suggests that sleeping habits should not be overlooked when prescribing a weight-reduction program to a patient with obesity. Sleep should be included as part of the lifestyle package that traditionally has focused on diet and physical activity."

http://www.sciencedaily.com/releases/2012/09/120917123926.htm

Living against the clock; Does loss of daily rhythms cause obesity?

August 29, 2012

Science Daily/Wiley

When Thomas Edison tested the first light bulb in 1879, he could never have imagined that this invention could one day contribute to a global obesity epidemic. Electric light allows us to work, rest and play at all hours of the day, and a new article suggests that this might have serious consequences for our health and for our waistlines.

 

Daily or "circadian" rhythms including the sleep wake cycle, and rhythms in hormone release are controlled by a molecular clock that is present in every cell of the human body. This human clock has its own inbuilt, default rhythm of almost exactly 24 hours that allows it to stay finely tuned to the daily cycle generated by the rotation of Earth. This beautiful symmetry between the human clock and the daily cycle of Earth's rotation is disrupted by exposure to artificial light cycles, and by irregular meal, work and sleep times. This mismatch between the natural circadian rhythms of our bodies and the environment is called "circadian desynchrony."

 

The paper, by Dr. Cathy Wyse, working in the chronobiology research group at the University of Aberdeen, focuses on how the human clock struggles to stay in tune with the irregular meal, sleep and work schedules of the developed world, and how this might influence health and even cause obesity.

 

"Electric light allowed humans to override an ancient synchronization between the rhythm of the human clock and the environment, and over the last century, daily rhythms in meal, sleep and working times have gradually disappeared from our lives," said Wyse. "The human clock struggles to remain tuned to our highly irregular lifestyles, and I believe that this causes metabolic and other health problems, and makes us more likely to become obese."

 

"Studies in microbes, plants and animals have shown that synchronization of the internal clock with environmental rhythms is important for health and survival, and it is highly likely that this is true in humans as well."

 

The human clock is controlled by our genes, and the research also suggests that some people may be more at risk of the effects of circadian desynchrony than others. For example, humans originating from Equatorial regions may have clocks that are very regular, which might be more sensitive to the effects of circadian desynchrony.

 

Shiftwork, artificial light and the 24-hour lifestyle of the developed world mean that circadian desynchrony is now an inevitable part of 21st century life. Nevertheless, we can help to maintain healthy circadian rhythms by keeping regular meal times, uninterrupted night-time sleep in complete darkness, and by getting plenty of sunlight during daylight hours.

 

Dr. Wyse believes that circadian desynchrony affects human health by disrupting the systems in the brain that regulate metabolism, leading to an increased likelihood of developing obesity and diabetes.

 

"The reason for the relatively sudden increase in global obesity in the developed world seems to be more complicated than simply just diet and physical activity. There are other factors involved, and circadian desynchrony is one that deserves further attention."

 

"Our 24-hour society has come at the high price of circadian desynchrony," concluded Wyse. "There are many factors driving mankind towards obesity but disrupted circadian rhythms should be considered alongside the usual suspects of diet and exercise."

http://www.sciencedaily.com/releases/2012/08/120829195119.htm

Weight Gain Induced by High-Fat Diet Increases Active-Period Sleep

July 10, 2012

Science Daily/Society for the Study of Ingestive Behavior

Research presented at the Annual Meeting of the Society for the Study of Ingestive Behavior (SSIB) finds that prolonged exposure to a high-fat diet reduces the quality of sleep in rats.

 

Using radio-telemetry, the authors measured 24-hour sleep and wake states after rats consumed a high fat diet for 8 weeks. Compared to rats that consumed a standard laboratory chow, the rats on the high-fat diet slept more but sleep was fragmented. The increased sleep time of the rats on the high-fat diet occurred mainly during the normally active phase of the day, resembling excessive daytime sleepiness observed in obese humans.

 

According to lead author, Catherine Kotz, "Studies in humans indicate a relationship between sleep quality and obesity. Our previous work in animals shows a link between good quality sleep, resistance to weight gain and increased sensitivity to orexin, a brain chemical important in stabilizing sleep and wake states. The current studies show that after high-fat diet-induced weight gain in rats, sleep quality is poor and orexin sensitivity is decreased. These findings suggest that poor sleep associated with weight gain due to a high-fat diet may be a consequence of reduced orexin sensitivity."

 

These studies highlight the impact of weight gain on sleep quality and a potential brain mechanism underlying these diet and weight-gain induced changes in sleep behavior.

http://www.sciencedaily.com/releases/2012/07/120710093804.htm

Brain Scans Show Specific Neuronal Response to Junk Food When Sleep-Restricted

June 10, 2012

Science Daily/American Academy of Sleep Medicine

The sight of unhealthy food during a period of sleep restriction activated reward centers in the brain that were less active when participants had adequate sleep, according to a new study using brain scans to better understand the link between sleep restriction and obesity.

 

Researchers from St. Luke's -- Roosevelt Hospital Center and Columbia University in New York performed functional magnetic resonance imaging (fMRI) on 25 men and women of normal weights while they looked at images of healthy and unhealthy foods. The scans were taken after five nights in which sleep was either restricted to four hours or allowed to continue up to nine hours. Results were compared.

 

"The same brain regions activated when unhealthy foods were presented were not involved when we presented healthy foods," said Marie-Pierre St-Onge, PhD, the study's principal investigator. "The unhealthy food response was a neuronal pattern specific to restricted sleep. This may suggest greater propensity to succumb to unhealthy foods when one is sleep restricted."

 

Previous research has shown that restricted sleep leads to increased food consumption in healthy people, and that a self-reported desire for sweet and salty food increases after a period of sleep deprivation. St-Onge said the new study's results provide additional support for a role of short sleep in appetite-modulation and obesity.

 

"The results suggest that, under restricted sleep, individuals will find unhealthy foods highly salient and rewarding, which may lead to greater consumption of those foods," St-Onge said. "Indeed, food intake data from this same study showed that participants ate more overall and consumed more fat after a period of sleep restriction compared to regular sleep. The brain imaging data provided the neurocognitive basis for those results."

http://www.sciencedaily.com/releases/2012/06/120610151447.htm

 

With Fat: What's Good or Bad for the Heart, May Be the Same for the Brain

May 18, 2012

Science Daily/Brigham and Women's Hospital

It has been known for years that eating too many foods containing "bad" fats, such as saturated fats or trans fats, isn't healthy for your heart. However, according to new research from Brigham and Women's Hospital (BWH), one "bad" fat -- saturated fat -- was found to be associated with worse overall cognitive function and memory in women over time. By contrast, a "good" fat -- mono-unsaturated fat was associated with better overall cognitive function and memory.

 

The research team analyzed data from the Women's Health Study -- originally a cohort of nearly 40,000 women, 45 years and older. The researchers focused on data from a subset of 6,000 women, all over the age of 65. The women participated in three cognitive function tests, which were spaced out every two years for an average testing span of four years. These women filled out very detailed food frequency surveys at the start of the Women's Health Study, prior to the cognitive testing.

 

"When looking at changes in cognitive function, what we found is that the total amount of fat intake did not really matter, but the type of fat did," explained Olivia Okereke, MD, MS, BWH Department of Psychiatry.

 

Women who consumed the highest amounts of saturated fat, which can come from animal fats such as red meat and butter, compared to those who consumed the lowest amounts, had worse overall cognition and memory over the four years of testing. Women who ate the most of the monounsaturated fats, which can be found in olive oil, had better patterns of cognitive scores over time.

 

"Our findings have significant public health implications," said Okereke. "Substituting in the good fat in place of the bad fat is a fairly simple dietary modification that could help prevent decline in memory."

 

Okereke notes that strategies to prevent cognitive decline in older people are particularly important. Even subtle declines in cognitive functioning can lead to higher risk of developing more serious problems, like dementia and Alzheimer disease.

http://www.sciencedaily.com/releases/2012/05/120518081358.htm

When You Eat Matters, Not Just What You Eat

May 17, 2012

Science Daily/Cell Press

When it comes to weight gain, when you eat might be at least as important as what you eat. That's the conclusion of a study reported in the Cell Press journal Cell Metabolism published early online on May 17th.

 

When mice on a high-fat diet are restricted to eating for eight hours per day, they eat just as much as those who can eat around the clock, yet they are protected against obesity and other metabolic ills, the new study shows. The discovery suggests that the health consequences of a poor diet might result in part from a mismatch between our body clocks and our eating schedules.

 

"Every organ has a clock," said lead author of the study Satchidananda Panda of the Salk Institute for Biological Studies. That means there are times that our livers, intestines, muscles, and other organs will work at peak efficiency and other times when they are -- more or less -- sleeping.

 

Those metabolic cycles are critical for processes from cholesterol breakdown to glucose production, and they should be primed to turn on when we eat and back off when we don't, or vice versa. When mice or people eat frequently throughout the day and night, it can throw off those normal metabolic cycles.

 

"When we eat randomly, those genes aren't on completely or off completely," Panda said. The principle is just like it is with sleep and waking, he explained. If we don't sleep well at night, we aren't completely awake during the day, and we work less efficiently as a consequence.

 

To find out whether restricted feeding alone -- without a change in calorie intake -- could prevent metabolic disease, Panda's team fed mice either a standard or high-fat diet with one of two types of food access: ad lib feeding or restricted access.

 

The time-restricted mice on a high-fat diet were protected from the adverse effects of a high-fat diet and showed improvements in their metabolic and physiological rhythms. They gained less weight and suffered less liver damage. The mice also had lower levels of inflammation, among other benefits.

 

Panda says there is reason to think our eating patterns have changed in recent years, as many people have greater access to food and reasons to stay up into the night, even if just to watch TV. And when people are awake, they tend to snack.

 

The findings suggest that restricted meal times might be an underappreciated lifestyle change to help people keep off the pounds. At the very least, the new evidence suggests that this is a factor in the obesity epidemic that should be given more careful consideration.

http://www.sciencedaily.com/releases/2012/05/120517132057.htm

Feeling Tired? 'Social Jetlag' Poses Obesity Health Hazard

May 10, 2012

Science Daily/Cell Press

Social jetlag -- a syndrome related to the mismatch between the body's internal clock and the realities of our daily schedules -- does more than make us sleepy. It is also contributing to the growing tide of obesity, according to a large-scale epidemiological study reported online on May 10 in Current Biology, a Cell Press publication.

 

"We have identified a syndrome in modern society that has not been recognized until recently," said Till Roenneberg of the University of Munich. "It concerns an increasing discrepancy between the daily timing of the physiological clock and the social clock. As a result of this social jetlag, people are chronically sleep-deprived. They are also more likely to smoke and drink more alcohol and caffeine. Now, we show that social jetlag also contributes to obesity; the plot that social jetlag is really bad for our health is thickening.

 

Their analysis shows that people with more severe social jetlag are also more likely to be overweight. In other words, it appears that living "against the clock" may be a factor contributing to the epidemic of obesity, the researchers say.

 

"Waking up with an alarm clock is a relatively new facet of our lives," Roenneberg says. "It simply means that we haven't slept enough and this is the reason why we are chronically tired. Good sleep and enough sleep is not a waste of time but a guarantee for better work performance and more fun with friends and family during off-work times." And slimmer waistlines, too.

http://www.sciencedaily.com/releases/2012/05/120510122802.htm

Lack of Sleep May Increase Calorie Consumption

March 14, 2012

Science Daily/American Heart Association

If you don't get enough sleep, you may also eat too much -- and thus be more likely to become obese. That is the findings of researchers who presented their study at the American Heart Association's Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism 2012 Scientific Sessions.

 

Participants ate as much as they wanted during the study.

 

Researchers found:

  • ·      The sleep deprived group, who slept one hour and 20 minutes less than the control group each day consumed an average 549 additional calories each day.

 

  • ·      The amount of energy used for activity didn't significantly change between groups, suggesting that those who slept less didn't burn additional calories.

 

  • ·      Lack of sleep was associated with increased leptin levels and decreasing ghrelin -- changes that were more likely a consequence, rather than a cause, of over-eating.

 

"Sleep deprivation is a growing problem, with 28 percent of adults now reporting that they get six or fewer hours of sleep per night," said Andrew D. Calvin, M.D., M.P.H., co-investigator, cardiology fellow and assistant professor of medicine at the Mayo Clinic.

 

The researchers noted that while this study suggests sleep deprivation may be an important part and one preventable cause of weight gain and obesity, it was a small study conducted in a hospital's clinical research unit.

http://www.sciencedaily.com/releases/2012/03/120314170456.htm

 

Obesity, Depression Found to Be Root Causes of Daytime Sleepiness

June 13, 2012

Science Daily/American Academy of Sleep Medicine

Three new studies conclude that obesity and depression are the main culprits making Americans excessively sleepy while awake. Researchers examined a random population sample of 1,741 adults and determined that obesity and emotional stress are the main causes of an "epidemic" of sleepiness and fatigue plaguing the country. Insufficient sleep and obstructive sleep apnea also play a role; both have been linked to high blood pressure, heart disease, stroke, depression, diabetes, obesity and accidents.

 

Wake up, America, and lose some weight -- it's keeping you tired and prone to accidents. Three studies being presented June 13 at sleep 2012 conclude that obesity and depression are the two main culprits making us excessively sleepy while awake.

 

Researchers at Penn State examined a random population sample of 1,741 adults and determined that obesity and emotional stress are the main causes of the current "epidemic" of sleepiness and fatigue plaguing the country. Insufficient sleep and obstructive sleep apnea also play a role; both have been linked to high blood pressure, heart disease, stroke, depression, diabetes, obesity and accidents.

 

"The 'epidemic' of sleepiness parallels an 'epidemic' of obesity and psychosocial stress," said Alexandros Vgontzas, MD, the principal investigator for the three studies. "Weight loss, depression and sleep disorders should be our priorities in terms of preventing the medical complications and public safety hazards associated with this excessive sleepiness."

 

In the Penn State cohort study, 222 adults reporting excessive daytime sleepiness (EDS) were followed up 7½ years later. For those whose EDS persisted, weight gain was the strongest predicting factor. "In fact, our results showed that in individuals who lost weight, excessive sleepiness improved," Vgontzas said.

 

Adults from that same cohort who developed EDS within the 7½-year span also were studied. The results show for the first time that depression and obesity are the strongest risk factors for new-onset excessive sleepiness. The third study, of a group of 103 research volunteers, determined once again that depression and obesity were the best predictors for EDS.

 

"The primary finding connecting our three studies are that depression and obesity are the main risk factors for both new-onset and persistent excessive sleepiness," Vgontzas said.

 

In the Penn State cohort study, the rate of new-onset excessive sleepiness was 8 percent, and the rate of persistent daytime sleepiness was 38 percent. Like insufficient sleep and obstructive sleep apnea, EDS also is associated with significant health risks and on-the-job accidents.

http://www.sciencedaily.com/releases/2012/06/120613091037.htm

 

Obesity and the Biological Clock: When Times Are out of Joint

May 10, 2012

Science Daily/Ludwig-Maximilians-Universitaet Muenchen (LMU)

Urgent appointments, tight work timetables and hectic social schedules structure modern life, and they very often clash with our intrinsic biological rhythms. The discrepancy results in so-called social jetlag, which can damage one's health. Among other effects, it can contribute to the development of obesity, as a new LMU study shows.

 

"Our surveys suggest that in Western societies two thirds of the population are burdened with a significant discrepancy between their internal time and the demands imposed by school and work schedules and leisure stress," says LMU chronobiologist Professor Till Roenneberg, who coined the term "social jetlag" to describe the phenomenon. If the rhythms dictated by our lifestyles are persistently out of phase with our biological clock, the risk of illness, such as high blood pressure and even cancer, rises.

 

Tired -- around the clock A team of researchers led by Roenneberg has now shown that social jetlag also contributes to another growing health problem, particularly in countries with a Western lifestyle -- obesity. Individuals who are overweight are at increased risk for serious metabolic diseases, such as diabetes. Many factors, in addition to excessive consumption of energy-rich foods, play a role in the development of obesity, and one of them is a lack of sleep. In persons who get too little sleep, the perception of hunger is perturbed, often leading to overeating.

 

And it is not just sleep duration that is important here. The LMU team has also found that social jetlag shows a significant association with increased body-mass index (BMI). The BMI, which is based on a quantitative relationship between weight and height, is used as a measure of body fat, and varies depending on age and sex.

 

Individuals with BMIs above the normal range are regarded as being overweight or obese. The results of the new study strongly indicate that a lifestyle that conflicts with our internal physiological rhythms can promote the development of obesity.

 

Moreover, it appears that the incidence of social jetlag is itself increasing, perhaps as a consequence of a general reduction in sleep duration."The ongoing debate on the usefulness of daylight-saving time (DST) should take note of our findings," remarks Roenneberg. "Just like conventional school and work schedules, DST disrupts our biological clock and subjects us to more social jetlag with all its consequences."

http://www.sciencedaily.com/releases/2012/05/120510132637.htm

New Research Explains How Proper Sleep is Important for Healthy Weight

May 7, 2012

Science Daily/Federation of American Societies for Experimental Biology

If you're counting calories to lose weight, that may be only part of the weight loss equation says a new research report published online in The FASEB Journal. In the report, French scientists show that impairments to a gene known to be responsible for our internal body clocks, called "Rev-Erb alpha," leads to excessive weight gain and related health problems. This provides new insights into the importance of proper alignment between the body's internal timing and natural environmental light cycles to prevent or limit excessive weight gain and the problems this weight gain causes.

 

According to Etienne Challet, Ph.D., a researcher involved in the work from the Department of Neurobiology of Rhythms at the Institute of Cellular and Integrative Neurosciences at the University of Strasbourg in Pascal, France,

 

"It is now clear that impairment of daily rhythms such as shift-work, exposure to artificial lighting, or jet-lag has multiple adverse effects on human health, every effort should be made to maintain or restore normal temporal organization and to avoid potentially disruptive behaviors such as nocturnal meals or light exposure at night."

 

To make this discovery, Challet and colleagues studied two groups of mice. One group was normal and the other group lacked the Rev-Erb alpha gene. In the mice lacking the Rev-Erb alpha gene, it was determined that they became obese and hyperglycaemic even if they ate the same quantity of food at the same time as normal mice.

 

Further scientific investigation showed that when the Rev-Erb alpha-deficient mice were compared to the normal mice, there was a major difference in the way Rev-Erb alpha-deficient mice metabolized the food they ate. The Rev-Erb alpha deficient mice created much more fat than the normal mice, and this occurred specifically during the feeding period. Additionally, the Rev-Erb-alpha deficient mice relied less on carbohydrate stores when at rest.

http://www.sciencedaily.com/releases/2012/05/120507113734.htm

Mid-afternoon slump? Why a sugar rush may not be the answer

Protein -- not sugar -- stimulates cells keeping us thin and awake, a new study suggests.

A new study has found that protein and not sugar activates the cells responsible for keeping us awake and burning calories. The research, published in the Nov. 17 issue of the scientific journal Neuron, has implications for understanding obesity and sleep disorders.

Wakefulness and energy expenditure rely on "orexin cells," which secrete a stimulant called orexin/hypocretin in the brain. Reduced activity in these unique cells results in narcolepsy and has been linked to weight gain.

Scientists at the University of Cambridge compared actions of different nutrients on orexin cells. They found that amino acids -- nutrients found in proteins such as egg whites -- stimulate orexin neurons much more than other nutrients.

"Sleep patterns, health, and body weight are intertwined. Shift work, as well as poor diet, can lead to obesity," said lead researcher Dr Denis Burdakov of the Department of Pharmacology and Institute of Metabolic Science. "Electrical impulses emitted by orexin cells stimulate wakefulness and tell the body to burn calories. We wondered whether dietary nutrients alter those impulses."

To explore this, the scientists highlighted the orexin cells (which are scarce and difficult to find) with genetically targeted fluorescence in mouse brains. They then introduced different nutrients, such as amino acid mixtures similar to egg whites, while tracking orexin cell impulses.

They discovered that amino acids stimulate orexin cells. Previous work by the group found that glucose blocks orexin cells (which was cited as a reason for after-meal sleepiness), and so the researchers also looked at interactions between sugar and protein. They found that amino acids stop glucose from blocking orexin cells (in other words, protein negated the effects of sugar on the cells).

These findings may shed light on previously unexplained observations showing that protein meals can make people feel less calm and more alert than carbohydrate meals.

"What is exciting is to have a rational way to 'tune' select brain cells to be more or less active by deciding what food to eat," Dr Burdakov said. "Not all brain cells are simply turned on by all nutrients, dietary composition is critical.

"To combat obesity and insomnia in today's society, we need more information on how diet affects sleep and appetite cells. For now, research suggests that if you have a choice between jam on toast, or egg whites on toast, go for the latter! Even though the two may contain the same number of calories, having a bit of protein will tell the body to burn more calories out of those consumed."

Mediterranean diet and exercise can reduce sleep apnea symptoms

November 28, 2011

Science Daily/European Lung Foundation

Eating a Mediterranean diet combined with physical activity can help to improve some of the symptoms of sleep apnea, according to new research. The study, which is published online in the European Respiratory Journal, looked at the impact a Mediterranean diet can have on obese people with sleep apnea, compared to those on a prudent diet.

 

Obstructive sleep apnea syndrome (OSAS) causes frequent pauses of breathing to occur during sleep, which disrupts a person's normal sleeping pattern. It is one of the most prevalent sleep-related breathing disorders with approximately 2-4% of the adult population experiencing the condition. This percentage increases up to 20-40% with obesity, and weight loss is often an essential part of the recommended treatment plan.

 

The researchers, from the University of Crete in Greece, examined 40 obese patients suffering from OSAS. Twenty patients were given a prudent diet to follow, while the other 20 followed a Mediterranean diet. Both groups were also encouraged to increase their physical activity, mainly involving walking for at least 30 minutes each day.

 

In both groups, the patients also received continuous positive airway pressure (CPAP) therapy which involves wearing a mask that generates an air stream, keeping the upper airway open during sleep.

 

The researchers monitored the patients during a sleep study, known as polysomnography. This involved monitoring several markers for OSAS, including electrical activity in the brain, eye movements and snoring. The patients were examined at the start of the study and again 6 months later.

 

The results showed that people following the Mediterranean diet had a reduced number of disturbances, known as apneas, during the rapid eye movement (REM) stage of sleep, which usually accounts for approximately 25% of total sleep during the night.

 

The findings also revealed that people following the Mediterranean diet also showed a greater adherence to the calorie restricted diet, an increase in physical activity and a greater decrease in abdominal fat.

 

The results of this small sample did show an improvement during one stage of sleep for people with sleep apnea, however it did not show an overall improvement in severity of the condition. The authors suggest that further studies in a larger sample are required to fully understand the benefits of this diet.

 

Christopher Papandreou, lead author for the research, said: "This is the first study examining the impact of the Mediterranean diet in combination with physical activity on OSAS via changes in the human body. Our results showed that the number of disturbances during REM sleep was reduced more in the Mediterranean diet group than the other group. Recent reports have related an increase in disturbances during REM sleep with the risk of developing significant systemic consequences like diabetes type II. However, its clinical significance remains unclear. Finally, more studies are needed to examine the effect of the above diet on this sleep-related breathing disorder taking into account its anti-inflammatory and antioxidant properties."

http://www.sciencedaily.com/releases/2011/11/111102093043.htm

Early to bed and early to rise: it's keeping kids leaner

September 30, 2011

Science Daily/American Academy of Sleep Medicine

Researchers recording the bedtimes and wake times of 2,200 Australian youths found that the night owls were 1.5 times more likely to become obese than the early birds, twice as likely to be physically inactive and 2.9 times more likely to sit in front of the TV and computer or play video games for more hours than guidelines recommend.

 

A study in the Oct. 1 issue of the journal Sleep recorded the bedtimes and wake times of 2,200 Australian participants, ages 9 to 16, and compared their weights and uses of free time over four days. Children who went to bed late and got up late were 1.5 times more likely to become obese than those who went to bed early and got up early. Furthermore, late-nighters were almost twice as likely to be physically inactive and 2.9 times more likely to sit in front of the TV and computer or play video games for more hours than guidelines recommend.

 

"The children who went to bed late and woke up late, and the children who went to bed early and woke up early got virtually the same amount of sleep in total," said co-author Carol Maher, PhD, a postdoctoral fellow with the University of South Australia. "Scientists have realized in recent years that children who get less sleep tend to do worse on a variety of health outcomes, including the risk of being overweight and obese. Our study suggests that the timing of sleep is even more important."

 

Maher said mornings are more conducive to physical activity for young people than nights, which offer prime-time TV programming and social networking opportunities. This relationship between time of day and available activities might explain why more sedentary and screen-based behaviors were observed with later bedtimes, she said. At a time when research is showing that teenagers have a natural tendency to stay up late and wake late, the results of this study could stand as a warning.

 

"It is widely accepted that the sleep patterns of adolescents are fundamentally different from children and adults, and that it is normal for adolescents to stay up very late and sleep in late in the morning," Maher said. "Our findings show that this sleeping pattern is associated with unfavorable activity patterns and health outcomes, and that the adolescents who don't follow this sleep pattern do better."

 

Other findings from the University of South Australia study:

 

  • ·      Early-bed/early-risers went to bed 70 to 90 minutes earlier, woke up 60 to 80 minutes earlier and accumulated 27 minutes more moderate to vigorous physical activity each day than late-risers.

 

  • ·      Late-bed/late-risers watched TV, played video games or were online 48 minutes longer each day than early-bed/early risers, primarily between 7 p.m. and midnight.

 

  • ·      Only 12 percent of late-bed/late-risers had an average of two hours or less screen time per day, which is recommended for children and teens by the Australian Department of Health and Aging. In comparison, 28 percent of early-bed/early risers met the recommendation for screen time.

 

  • ·      On a broad scale, late-bed/late-risers replaced about 30 minutes of moderate to vigorous physical activity with 30 minutes of sedentary behavior each day, relative to the early-bed/early-rise group.

 

  • ·      Body-mass index (BMI) scores were higher in late-risers than early-risers, and late-risers were more likely to be overweight or obese.

 

  • ·      Late-bed/late-risers tended to have few siblings, live in major cities, come from lower household incomes and have a part-time job.

http://www.sciencedaily.com/releases/2011/09/110930052216.htm

Mindless eating: Losing weight without thinking

August 6, 2011

Science Daily/American Psychological Association

Dieters may not need as much willpower as they think, if they make simple changes in their surroundings that can result in eating healthier without a second thought, said a consumer psychologist at the American Psychological Association's 119th Annual Convention.

 

"Our homes are filled with hidden eating traps," said Brian Wansink, PhD, who presented his findings and strategies for a healthier lifestyle in a plenary address entitled "Modifying the Food Environment: From Mindless Eating to Mindlessly Eating Better."

 

"Most of us have too much chaos going on in our lives to consciously focus on every bite we eat, and then ask ourselves if we're full. The secret is to change your environment so it works for you rather than against you," Wansink said

 

Wansink identified several myths about eating behaviors as a way to explain why Americans, on average, have been getting fatter. "People don't think that something as simple as the size of a bowl would influence how much an informed person eats," he said.

 

However, several studies show exactly that, including Wansink's study of 168 moviegoers, who ate either fresh or stale popcorn from different size containers. People ate 45 percent more fresh popcorn from extra-large containers than large ones and the people who were eating stale popcorn ate 34 percent more from the extra-large buckets than people eating fresh popcorn, according to the study.

 

They just don't realize they're doing it," said Wansink. This strategy also applies to what we drink. His research found that people pour about 37 percent more liquid in short, wide glasses than in tall, skinny ones of the same volume.

 

Even a kid's cereal bowl can be a trap, according to Wansink. One study showed children of different weights who were given a 16 ounce bowl were more likely to serve themselves twice as much cereal than children given an 8 ounce bowl.

 

Another myth, according to Wansink, is that people know when they are full and stop before they overeat. His Food and Brand Lab at Cornell University tested this by designing a "bottomless bowl." They brought in 60 people for a free lunch and gave 22 ounce bowls of soup to half, while the other half unknowingly got 22 ounce bowls that were pressure-fed under the table and slowly refilled. The results: people with bottomless bowls ate 73 percent more than those with normal bowls, yet when asked, they didn't realize they had eaten more. "The lesson is, don't rely on your stomach to tell you when you're full. It can lie," Wansink said.

 

Simply being aware of such findings can help people make healthier choices, especially those who are already trying to eat healthier foods, according to Wansink. One of his studies showed that people lost up to two pounds a month after making several simple changes in their environment, including:

 

  • ·      eating off salad plates instead of large dinner plates.
  • ·      keeping unhealthy foods out of immediate line of sight and moving healthier foods to eye-level in the cupboard and refrigerator.
  • ·      eating in the kitchen or dining room, not in front of the television.

 

"These simple strategies are far more likely to succeed than willpower alone. It's easier to change your environment than to change your mind," Wansink concluded.

http://www.sciencedaily.com/releases/2011/08/110805163541.htm

Think healthy, eat healthy: Scientists show link between attention and self-control

August 10, 2011

Science Daily/California Institute of Technology

You're trying to decide what to eat for dinner. Should it be the chicken and broccoli? The super-sized fast-food burger? Skip it entirely and just get some Rocky Road?

Making that choice, it turns out, is a complex neurological exercise. But, according to researchers from the California Institute of Technology (Caltech), it's one that can be influenced by a simple shifting of attention toward the healthy side of life. And that shift may provide strategies to help us all make healthier choices -- not just in terms of the foods we eat, but in other areas, like whether or not we pick up a cigarette.

Their research is described in a paper published in the July 27 issue of the Journal of Neuroscience.

When you decide what to eat, not only does your brain need to figure out how it feels about a food's taste versus its health benefits versus its size or even its packaging, but it needs to decide the importance of each of those attributes relative to the others. And it needs to do all of this more-or-less instantaneously.

Antonio Rangel, professor of economics and neuroscience at Caltech, has been studying this value-deriving and decision-making process for years now. Along with Todd Hare -- a former postdoc at Caltech who is now an assistant professor of neuroeconomics at the University of Zurich in Switzerland -- he published a paper in Science in 2009 describing differences in the brains of people who are better at exercising self-control than others. What they found was that while everyone uses the same area of the brain -- the ventral medial prefrontal cortex, or vmPFC -- to make value-laden decisions like what to munch on, there's a second brain area -- the dorsolateral prefrontal cortex, or dlPFC -- that seems to come to life when a person is using self-control during the decision-making process.

In other words, when the dlPFC is active, it allows the vmPFC to take into account health benefits as well as taste when it assigns a value to a particular food.

The new study goes a step further, showing that there seem to be ways to help kickstart the dlPFC through the use of what Hare calls "external cues" that allow us to exhibit more self-control than we might have otherwise.

The researchers came to their conclusions based on data from a brain-imaging experiment conducted with 33 adult volunteers, none of whom were following a specific diet or trying to lose weight for any reason. Each of the volunteers was shown 180 different food items -- from chips and candy bars to apples and broccoli -- through a set of video goggles while in a functional magnetic resonance imaging (fMRI) machine.

The hungry subjects -- they were asked to fast for at least three hours prior to the experiment -- were given up to three seconds to respond to each picture with a decision about whether or not they'd want to eat the food shown after the experiment was over. They could either give the food a "strong no," a "no," a "yes," or a "strong yes." Once all of the images had been flipped through, a single food image was chosen at random; if the volunteer had said "yes" or "strong yes" to the idea of eating that food, he or she was served that item.

"Because only one random trial was selected to 'count,'" says Rangel, "the optimal strategy for subjects is to treat each decision as if it were the only one."

Simple, right? But here's the catch: before every 10 food choices, an instruction would come on the screen for five seconds telling the subjects either to "consider the healthiness," "consider the tastiness," or "make decisions naturally." This meant that of the 180 decisions, the subjects made 60 in each of the three "instruction conditions."

What this was meant to do, Rangel explains, is shift the subject's attention during the experiment and, potentially, shift the way in which they made decisions.

Afterward -- outside the scanner -- the subjects were asked to rate the same foods on both a tastiness scale (very untasty, untasty, tasty, very tasty) and a healthiness scale (very unhealthy, unhealthy, healthy, very healthy). That way, the researchers were able to associate the choices the subjects made during the brain scan with their stated perceptions of those foods' attributes -- showing that a subject who chose broccoli during the "consider the healthiness" portion of the test might think of it nonetheless as untasty.

The researchers then classified the foods for each subject based on that subject's ratings: unhealthy-untasty, healthy-untasty, unhealthy-tasty, and healthy-tasty. Unsurprisingly, people chose healthy-tasty foods no matter where their attention had been directed.

Things got interesting when the researchers looked at the other three categories, however. Among their findings:

  • When thinking about healthiness, subjects were less likely to eat unhealthy foods, whether or not they deemed them to be tasty, and more likely to eat healthy-untasty foods.
  • Being asked to think about healthiness led subjects to say "no" to foods more often than they did when asked to make decisions naturally.
  • There were no real differences between the choices made during the "consider the tastiness" and "make decisions naturally" portions of the experiment.

When the researchers turned to the fMRI results, they found that the vmPFC was, as predicted, "more responsive to the healthiness of food in the presence of health cues," says Rangel. And, as they'd seen previously, the robustness of that response was due to the influence of the dlPFC -- that bastion of self-control -- which was much quieter when the study's subjects were thinking about taste or their own personal choice than when they were asked to throw healthiness into the equation.

"This increased influence of the health signals on the vmPFC results in an overall value for the food that is based more on its health properties than is the case when the subject's attention is not focused on healthiness," says Hare.

These results are most likely not limited just to choices about food, Hare says. "Our findings are also relevant to the current changes to cigarette warnings many governments have started to make," he notes. "These changes include adding graphical images of the health risks of smoking. It remains to be seen whether these images will be more effective in drawing attention to the unhealthiness of smoking than the text warnings. If the graphical warnings do increase attention to health, then our results suggest that they could decrease the desire to smoke."

Jonathan Malmaud, a former research assistant at Caltech who is now a graduate student at MIT, was also an author on the Journal of Neuroscience paper, "Focusing attention on the health aspects of foods changes value signals in the vmPFC and improves dietary choice." The scientists' work was funded by a grant from the National Science Foundation.

http://www.sciencedaily.com/releases/2011/07/110727122815.htm

 

'Love your body' to lose weight

July 18, 2011

Science Daily/BioMed Central Limited

Almost a quarter of men and women in England and over a third of adults in America are obese. Obesity increases the risk of diabetes and heart disease and can significantly shorten a person's life expectancy. New research published by BioMed Central's open access journal International Journal of Behavioral Nutrition and Physical Activity shows that improving body image can enhance the effectiveness of weight loss programs based on diet and exercise.

 

Researchers from the Technical University of Lisbon and Bangor University enrolled overweight and obese women on a year-long weight loss program. Half the women were given general health information about good nutrition, stress management, and the importance of looking after yourself. The other half attended 30 weekly group sessions (the intervention plan) where issues such as exercise, emotional eating, improving body image and the recognition of, and how to overcome, personal barriers to weight loss and lapses from the diet were discussed.

 

On the behavioral intervention plan women found that the way they thought about their body improved and that concerns about body shape and size were reduced. Compared to the control group they were better able to self-regulate their eating and they lost much more weight, losing on average 7% of their starting weight compared to less than 2% for the control group.

 

Dr. Teixeira from Technical University of Lisbon, who led the research, said, "Body image problems are very common amongst overweight and obese people, often leading to comfort eating and more rigid eating patterns, and are obstacles to losing weight.

 

Our results showed a strong correlation between improvements in body image, especially in reducing anxiety about other peoples' opinions, and positive changes in eating behavior. From this we believe that learning to relate to your body in healthier ways is an important aspect of maintaining weight loss and should be addressed in every weight control program."

http://www.sciencedaily.com/releases/2011/07/110717204913.htm

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