Why sleep needs to be part of your weight loss strategy

When we need to lose weight the first thing we think about is giving up our daily muffin fix and putting in some quality time at the gym. While I encourage both healthy eating and exercise, what about getting more sleep as a weight loss strategy? Who wouldn’t want some of that? It’s free and requires no special equipment…well, unless you want to go all designer silk pajamas and one million thread count Egyptian cotton sheets.

1.4 billion adults and 250 million children world-wide are obese ¹. Obesity and its subsequent detrimental health effects (cardiovascular disease, diabetes, and non alcoholic fatty liver disease) is the biggest health challenge of our time. While excessive consumption of high calorie foods combined with reduced physical activity is the key driver of this epidemic the latest research is also focusing on other factors that have changed in the last century.

Fifty years ago the average person was getting 1.5-2 hours more shut-eye per night than we are now ². This means we have reduced our weekly time between the sheets by 14 hours (2 nights of full sleep for most of us) or, 4 weeks of lost sleep over the year. That’s a pretty hefty sleep deficit. Science is now revealing the alarming (no pun intended) consequences for our wellbeing. Is there a correlation between lack of sleep and obesity? Science says, “Yes”.

Why does lack of sleep make you gain weight?

Leptin and grehlin dysregulation

How much you eat is controlled to by an appetite centre located in the hypothalamus of the brain. Two of the key hormones that communicate with this centre are the “No more, thanks I’m full” hormone, leptin and the “I can eat ALL the food NOW” grehlin. Habitual partial sleep deprivation of 6 hours or less per night causes a decrease of leptin and an increase of grehlin. This is a double whammy. You feel hungrier AND your body has less ability to communicate that actually you do have enough fuel in the tank. Net result is you are more likely to overeat. To make things worse the increased hunger usually results for cravings of carbohydrate rich, fatty food ³. Bad news in Western society where we have an abundance of ready to go unhealthy carbohydrate rich snacks… pass me the chips and donuts.

This increased appetite signaling may be a psychological adaptation to ensure the brain – one of the most metabolically active organs in the body – has enough energy to remain awake longer ¹.

Cortisol

It’s not just the quantity of sleep that affects your metabolism quality matters as well. Slow wave sleep happens during the first couple of sleep cycles in the night. It’s the time where the body cleans out the garbage, repairs and resets. Cortisol should drop during this time to enhance insulin sensitivity allowing optimal metabolism of carbohydrates. Things that mess with slow wave sleep like alcohol and prescription sleeping medications can have a detrimental effect on blood sugar control and weight management leading to the dreaded abdominal fat ³.

Less inclined to exercise

Lack of sleep leaves you feeling tired, irritable and fatigued so the motivation to exercise drops. Who wants to do something that will tire you out when you’re already exhausted? This results in less energy expenditure and is a risk factor for weight gain ³.

Poor food choices

Good decision making declines with insufficient sleep. You are less likely to make nutritious food choices or have the motivation to cook a healthy meal. Because you are feeling tired food high in sugar that gives you a temporary rise in energy becomes very attractive ⁴. All aboard the blood sugar roller coaster!

More time to eat

Being awake longer gives you more opportunity to consume food. People who go to bed later or have trouble sleeping are more likely to consume calories between 10pm and 4:00am. A 2013 study showed than people who chronically suffered from a lack of sleep ate smaller breakfasts but consumed more calories during the day especially carbohydrates and fats after the evening meal¹.

This causes havoc with our metabolism as our circadian cycle in not set up to optimise processing of carbohydrates and fat during this time. This is one of the reason shift workers have a higher risk of developing diabetes ⁵.

Inflammation

A lack of sleep increases the bad boys of inflammation namely interleukin -6 and tumour necrosis factor alpha. Inflammation causes our old friend leptin to not to work as it should. Inflammation also increases insulin resistance that leads to weight gain and even more inflammation creating a vicious cycle ⁶. Getting quality sleep in conjunction with diet and exercise will keep inflammation in check.

People who sleep 6hrs or less per night consume, on average, between 1,200-2,000 extra kilojoules per day ³. That’s the equivalent of one extra meal.

It’s time to add sleep as part of your weight loss strategy. You’ll regulate your appetite, make better food choices, reduce inflammation and balance your blood sugar. That’s a pretty good outcome for just lying around!

References:

1. Markwald RR, Melanson EL, Smith MR, et al. Impact of insufficient sleep on total daily energy expenditure, food intake and weight gain. Proc Natl Acad Sci U S A. 2013;110(14):5695–5700. doi:10.1073/pnas.1216951110.
2. Van Cauter E, Spiegel K, Tasali E, Leproult R. Metabolic consequences of sleep and sleep loss. Sleep Med. 2008;9(SUPPL. 1):1–11. doi:10.1016/S1389-9457(08)70013-3.
3. Spaeth AM, Dinges DF, Goel N. Effects of experimental sleep restriction on weight gain, caloric intake, and meal timing in healthy adults. Sleep. 2013;36:981–990. doi:10.5665/sleep.2792.
4. Schmid SM, Hallschmid M, Jauch-Chara K, Born J, Schultes B. A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal-weight healthy men. J Sleep Res. 2008;17(3):331–334. doi:10.1111/j.1365-2869.2008.00662.x.
5. Lowson E, Middleton B, Arber S, Skene DJ. Effects of night work on sleep, cortisol and mood of female nurses, their husbands and children. Sleep Biol Rhythms. 2013;11(1):7–13. doi:10.1111/j.1479-8425.2012.00585.x.
6. Eisele H-J, Markart P, Schulz R. Obstructive Sleep Apnea, Oxidative Stress, and Cardiovascular Disease: Evidence from Human Studies. Oxid Med Cell Longev. 2015;2015:608438. doi:10.1155/2015/608438.