Dr. Sharma's Obesity Notes

Regular readers are well aware of the increasing evidence that points to a major role for sleep deprivation in the current obesity epidemic. Indeed, one of the most evident societal changes coinciding with the epidemic spread of excess weight is the significant reduction in sleeping hours - in both kids and adults.

Now a study by Orfeo Buxton and colleagues from Harvard University, published in Science Translational Medicine, shows just how profoundly sleep restriction and disruption of sleep cycles can affect your metabolism.

The experiments were designed to tested the hypotheses that prolonged sleep restriction with concurrent circadian disruption, as can occur in people performing shift work, impairs glucose regulation and metabolism.

Healthy adults were recruited to spend at least five weeks under controlled laboratory conditions in which they experienced an initial baseline segment of optimal sleep, three weeks of sleep restriction (5.6 hours of sleep per 24 hours) combined with circadian disruption (recurring 28-hour “days”), followed by 9 days of recovery sleep with circadian re-entrainment.

Not only die sleep restriction with concurrent circadian disruption markedly decrease participants’ resting metabolic rates but these interventions also increased plasma glucose concentrations after a meal, due to reduced pancreatic insulin secretion.

Nine days of recovery sleep normalized all of these changes.

Interestingly enough, a recent study by Korean researchers, published in the Journal of Sleep Research, looking at the relationship between sleeping patterns and body weight in almost 1,000 school children (48.2% boys) aged 10 or 11 found that, after adjusting for relevant confounding variables (age, sex, breakfast eating, screen time and parental obesity), longer sleep on weekdays and weekends was associated with 30% decreased odds of excess weight.

Perhaps, more importantly (and in line with the Harvard study), kids who slept little during the week but managed to catch up on their sleep deficit on the weekends also had a lower risk of excess weight.

Together these findings support the notion that sleep hygiene may be an important target for intervention in weight management and, at a population level, may well be an issue that may deserve as much attention and discussion as health eating and physical activity.

Is it time for a Canada Sleep Guide?

AMS
Calgary, Alberta

Buxton OM, Cain SW, O’Connor SP, Porter JH, Duffy JF, Wang W, Czeisler CA, & Shea SA (2012). Adverse metabolic consequences in humans of prolonged sleep restriction combined with circadian disruption. Science translational medicine, 4 (129) PMID: 22496545

Kim CW, Choi MK, Im HJ, Kim OH, Lee HJ, Song J, Kang JH, & Park KH (2012). Weekend catch-up sleep is associated with decreased risk of being overweight among fifth-grade students with short sleep duration. Journal of sleep research PMID: 22494030

Regular readers will be well aware of the emerging evidence that quality and amount of sleep can have profound effects on eating behaviour and may well be an important factor in the development of obesity.

A study by Marie-Pierre St-Onge and colleagues from Columbia University, New York, in a paper published in the American Journal of Clinical Nutrition, used functional Magnetic Resonance Imaging (fMRI) to examine the effect of sleep restriction on brain regions sensitive to food stimuli.

The researchers studied 30 healthy, normal-weight men and women for a 2-phase inpatient crossover study in which they spent either 4 h/night (restricted sleep) or 9 h/night (habitual sleep) in bed.

Overall neuronal activity in response to food stimuli was significantly greater after restricted sleep than after habitual sleep, particularly in areas associated with reward, cognitive processing, decision-making, and self-control, including the putamen, nucleus accumbens, thalamus, insula, and prefrontal cortex.

The findings of this study link restricted sleep and susceptibility to food stimuli and are consistent with the notion that reduced sleep may lead to greater propensity to overeat.

“These changes associated with reduced sleep apparently affect brain regions known to be linked to motivation and desire and may indicate an increased propensity to seek food in individuals who are not getting enough sleep. These actions, in a world where food is readily accessible, would promote weight gain. Overall, these findings suggest that changes in neuronal activity in response to food stimuli after insufficient sleep are precursors to energy balance regulation mechanisms in the brain.”

Certainly more evidence that lack of sleep may be driving those cravings and impulsive eating that could be contributing to weight gain.

AMS
Edmonton, Alberta

St-Onge MP, McReynolds A, Trivedi ZB, Roberts AL, Sy M, & Hirsch J (2012). Sleep restriction leads to increased activation of brain regions sensitive to food stimuli. The American journal of clinical nutrition PMID: 22357722

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Regular readers of these pages will be well aware of the recent slew of evidence suggesting that not getting enough sleep is an important risk factor for weight gain (as anyone who works shifts probably knows from their own experience).

But, as always, not everyone appears to be equally affected.

A paper by Jean-Philippe Chaput and colleagues from the University of Ottawa, just published in SLEEP, suggests that sleep deprivation may especially tend to promote weight gain in people who tend to be disinhibited eaters.

Based on the examination of 276 adults aged 21 to 64 years and followed for 6 years in the Quebec Family Study, Chaput and colleagues found that individuals having both short sleep duration (loss than 6 hours a night) and high disinhibition eating behaviour (as assessed by the three factor eating questionnaire) were more likely to gain weight and increase their abdominal circumference over time.

In contrast, short-duration sleepers with a low disinhibition eating behavior trait had the same weight trajectory as those with average sleep duration.

Over the 6-year follow-up period, the incidence of overweight/obesity for short-duration sleepers with a high disinhibition eating behavior trait was 2.5 times more frequent than for short-duration sleepers with a low disinhibition eating behavior trait.

This increased risk of high disinhibition in short-duration sleepers was largely explained by higher caloric intake.

For those of us still dealing with leftovers from yesterday’s turkey, getting enough sleep may help with any ‘disinhibition’ we may experience when opening the refrigerator.

AMS
Edmonton, Alberta

Chaput JP, Després JP, Bouchard C, & Tremblay A (2011). The Association between Short Sleep Duration and Weight Gain Is Dependent on Disinhibited Eating Behavior in Adults. Sleep, 34 (10), 1291-7 PMID: 21966060

Today’s post is another excerpt from “Best Weight: A Practical Guide to Office-Based Weight Management“, recently published by the Canadian Obesity Network.

This guide is meant for health professionals dealing with obese clients and is NOT a self-management tool or weight-loss program. However, I assume that even general readers may find some of this material of interest.

CHAPTER 5: MEDICAL BARRIERS

Physical co-morbidities are common in people with obesity and need to be addressed as part of any weight-management plan. Co-morbidities associated with obesity will improve as weight is controlled, but often make it difficult for patients to undertake the effort required for lifestyle-based weight management. In some cases, these physical barriers to weight loss may be insurmountable and the focus of treatment should, from the outset, aim to prevent weight gain rather than achieve weight loss. Strategies for obesity treatment should always be adapted to the patient’s particular situation to make it easier for them to cope with required changes over the long-term.

SLEEP DISORDERS

Sleep disorders are very prevalent among obese people. Obstructive sleep apnea is the most common disorder, but disturbed sleep may also be due to primary insomnia, or insomnia secondary to medications, medical or psychiatric disorders.

Sleep deprivation is linked to obesity. The primary putative connection can be found in the neuroendocrine regulation of appetite and food intake. Neuroendocrine regulation appears to be influenced by sleep duration and sleep restriction, with sleep deprivation favouring obesity as it increases serum cortisol and decreases serum leptin levels. Another reason for the sleep disorder-obesity connection may be simply that the more time a person spends awake, the more time they have in which to eat.

Insufficient sleep causes important neurocognitive changes such as excessive daytime sleepiness, fatigue and altered mood. These may, in turn, have a significant impact on the patient’s ability to persist with healthy lifestyle changes such as increasing their level of physical activity or taking the time to cook a healthy meal.

© Copyright 2010 by Dr. Arya M. Sharma and Dr. Yoni Freedhoff. All rights reserved.

The opinions in this book are those of the authors and do not represent those of the Canadian Obesity Network.

Members of the Canadian Obesity Network can download Best Weight for free.

Best Weight is also available at Amazon and Barnes & Nobles (part of the proceeds from all sales go to support the Canadian Obesity Network)

If you have already read Best Weight, please take a few minutes to leave a review on the Amazon or Barnes & Nobles website.

Readers will recall a post earlier this week on the importance of sleep for weight management.

Researchers and clinicians, wanting to know more about the underlying biology and mechanisms on how lack of sleep, disruption of circadian rhythm (e.g. through shift work, jet lag, or having a baby), and alterations in light/dark cycles can impact ingestive behaviour and energy metabolism may wish to read a comprehensive review just published in the Annals of Medicine.

In this paper, Russel Reiter and colleagues from the University of Texas, San Antonio, summarize the potential contributions of three processes that may be contributing to humans becoming progressively more overweight: circadian or chronodisruption, sleep deficiency, and melatonin suppression.

As the authors point out:

“Circadian disruption, sleep deficiency, and melatonin suppression have at least one common causative feature, i.e. excessive light exposure including even brief periods of light at night. Indeed, interrupting the normal dark period with a short interval of bright light may be the most disruptive. Certainly, light pollution throughout the world, and especially in the economically well developed and developing nations, where obesity is also the most common, has become a major problem and is a serious concern. The use of artificial light after darkness onset in the evening and in the morning before sunrise is commonplace and impacts the physiology of the circadian system which influences both nocturnal melatonin synthesis and sleep. Moreover, being exposed to light after darkness onset due to what is referred to as trespass light or intentionally turning on a lamp is disruptive to the circadian system, which reduces melatonin levels and disturbs sleep.“

Obviously, looking at bright light sources such as a TV, a computer screen or a backlit e-Book can be even more disruptive.

Perhaps we should now all plan for candle-light dinners and then call it an early night?

AMS
Leipzig, Germany

Reiter RJ, Tan DX, Korkmaz A, & Ma S (2011). Obesity and metabolic syndrome: Association with chronodisruption, sleep deprivation, and melatonin suppression. Annals of medicine PMID: 21668294