Could a lack of sleep encourage weight gain? Or simply unhealthy eating? Scientific evidence suggests that it does.
How does sleep affect weight?
Sleep impacts endocrine (hormonal) regulation of our energy balance (energy intake versus energy expenditure).
Many studies have now shown that an acute deprivation of sleep is associated with decreased leptin levels and increased ghrelin levels. These effects have been seen independently of age, sex and BMI. To understand how this works, we first of all need to know a little bit about leptin and ghrelin.
What is leptin?
Leptin is a protein produced by adipocytes (fat cells). The amount secreted is based on the mass of adipose tissue (fat) an individual has – more is released in individuals who are overweight/ obese than those who are lean and therefore have less adipose tissue.
Leptin plays an important role in the regulation of energy balance. It sends messages to the brain that signal for the cessation of food intake and the regulation of body weight/ stimulation of metabolic rate. It is classed as an anorexigenic factor, which is a hormone, compound or drug that works as an appetite suppressor.
The leptin feedback mechanism
It has however been postulated that obese individuals have leptin resistance, allowing them to eat more despite the appetite inhibiting effects of leptin. Leptin resistance could be due to an increase in C-reactive protein (CRP) – a protein that is increased with obesity and also sleep loss [1]. Leptin binds to circulating CRP and this can lead to decreased effectiveness of leptin [1].
What is ghrelin?
Ghrelin is produced by the stomach and signals for hunger. It is known as an orexigenic hormone – orexigenic compounds, hormones or drugs work to stimulate appetite. Levels of ghrelin are lower in obese individuals and higher in lean individuals. Once you have eaten, ghrelin levels are reduced.
Factors influencing the release of ghrelin:
| Regulators of circulating ghrelin | Effect on circulating ghrelin |
| Food intake | Decreases |
| Age | Decreases with increasing age |
| Gender | Increased levels in females over males |
| BMI | Decreases with increasing BMI |
| Glucose | Decreases |
The above table was adapted from Klok M et Al. [2]
What is the role of sleep in weight management
Putting it all together…
Increased appetite
The levels of circulating leptin are depressed in sleep deprived individuals. This results in a lesser amount of control over the regulation/ suppression of appetite. This means that we can eat more than normal before our body tells us we have had enough.
To confound matters, an increase in ghrelin levels is also associated with sleep deprivation. This increases appetite and consequently the amount of food we desire. These two things together therefore influence the quantity of food we want to eat which is generally more than we would normally eat if we had received a good night sleep. There has even been a direct association between short sleep duration and an increased BMI [3].
Altered eating habits
An increase in irregular eating habits is also seen with reduced sleep duration. For instance, increased snacking between meals reduced vegetable intake and food choices that are more energy dense. This can be tied to the physiological changes of ghrelin and leptin secretion and also the emotional side effects experienced with sleep deprivation e.g. the tendency to want comfort foods or feeling as though more food is needed to provide additional energy to get through the day.
Decreased physical activity
Another potential reason for weight gain is that we are generally less inclined to be as active if we are feeling fatigued. So with sleep deprivation, appetite is increased yet physical activity is decreased. This can easily throw off the energy input vs. output balance.
The diagram below sums up these potential causes for weight gain due to lacking sleep.
The above diagram was taken from The Metabolic Consequences of Sleep Deprivation [1].
× NEAT stands for Non-exercise activity thermogenesis which is the energy we expend for everything bar sleep, sport or eating. Examples include walking, household chores, typing and fidgeting – these are incidental activities that can increase metabolic rate.
Getting the best night sleep you can, could therefore assist in weight loss and weight management – it will help with control over the amount we eat and making healthier choices.
Tips for improved sleeping habits
√ Have a routine that your body can adapt to. Having a mix of late nights and late mornings will throw your body clock out and make it more difficult to get sleep.
√ Avoid using electronic devices immediately before bed e.g. watching TV or playing video games. It can take longer for your brain to switch off.
√ Turn off your mobile phone or set it to the ‘do not disturb mode’.
√ Make sure you don’t go to bed extremely hungry or too full. You may be too focused on these issues to fall asleep.
√ Try not to drink too much fluid just before bed so you aren’t disturbed by needing to get up throughout the night.
√ Make sure you are comfortable e.g. ensure the room is dark enough and quiet enough.
For more advice on weight management, see my blog on ‘Healthy Weight Loss’.
Contact us for results focused advice about eating healthy
For more information about weight management, make an appointment with our dietitian Belinda Elwin. ENT Wellbeing can be reached on 1300 123 368 and are happy to help with any diet related issues or questions.
Contact us today!
References
1. Knutson K, Spiegel K, Cauter E. The Metabolic Consequences of Sleep Deprivation. Sleep Medical Review. 2007 June; 11(3): 163 – 178.
2. Klok M, Jakobsdottir S, Drent M. Appetite Regulatory Peptides: The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review. Department of Endocrinology, VU University Medical Center. Revised 9th March 2006.
3. Taheri S, Lin L, Austin D, Young T, Mignot E. Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index. December 2004; 1(3)
