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By Bonny Chow – Dietitian

Simply put, the answer is: YES! 

We spend one-third of our lives sleeping, and for good reasons. Quality sleep
is a vital for immunity,  brain function, mental health, muscle and injury repair, regulation of hormones, and toxin removal (1).

Lack of sleep makes you want to eat, even when your body doesn’t require food. Staying up late, waking up tired and needing a caffeine hit to get you moving in the morning sets you up for that 3pm slump,  sugar cravings-control that are out-of and lack of motivation to exercise.  It’s a familiar pattern many sleep-deprived people experience. This article explores how quality sleep plays a fundamental role in weight management.

Effects of poor sleep

Poor energy levelswith lack of sleep, the body has insufficient time to recover from physical and psychological burden (eg. muscle soreness and stress). Poor rest and recovery can accumulate into fatigue and decreased your productivity.  Many people turn to excessive caffeine and sugar intake for an energy boost to get them through.  On top of the cravings for sugary pick-me-ups, blood sugar and insulin levels become unstable, causing additional hunger, cravings and poor energy levels (2). This results in increased energy demands on the brain during prolonged wakefulness, increasing your feelings of hunger (3).

Impaired attention, reaction time, memory, thinking, learning, creative thinking – with poor cognitive function it can be tempting to choose unhealthy food options to satisfy a roaring appetite, and to boost energy levels. However, this effect is short lived where the need for more food is signalled. Decision making can also be compromised especially when you want to feel better immediately. Impaired food choices can lead to grabbing something on-the-go (eg. pastries, muffins, chocolate or chips), resulting in weight gain (4).

Poor tolerance to stressour endocrine function, responsible for hormone control, has a complex response to sleep. Some hormones are released during certain sleep stages such as growth hormone secreted within the first two hours of sleep, whereas cortisol peaks in late afternoon, and works with your internal body clock. With low stress tolerance, it can lead to over secretion of cortisol, causing belly weight gain, with difficulty in unwinding at the end of the day (5).

Irritability, anxiety, depression and mood disorders– neurotransmitter function is sensitive to insufficient sleep, thereby poor sleep can affect healthy neurotransmitter production of serotonin and dopamine (feel good brain chemicals) (6). Some people tend to reach for sweets or junk food to give themselves temporary relief from feeling anxious, depressed or stressed. This is called emotional eating. You’re physiology not hungry for energy and nutrients, but use eating as a coping mechanism. This contributes to excess weight gain.

Inflammation- cortisol (a hormone that responds to stress) has anti-inflammatory effects, so with an imbalance of cortisol from insufficient rest, the body can experience low-grade inflammation. Inflammatory conditions can include arthritis, joint pain, skin problems, brain fog, and gut issues; low-grade inflammation is associated with Type 2 Diabetes and cardiovascular disease (7). Furthermore, a study reports the opioid system (for pain relief) can be suppressed, including proper function of serotonin system that supports pain inhibition, which are both negatively affected by lack of deep sleep or continued sleep disturbance (8).

Poor immune functionimmune cells are highest during early stages of sleep (T helper cells and antigen presenting cells), this allows an adaptive immune response against foreign invaders (eg. cold virus). A study reported that poor immunity can be the result of suppressed immune boosting cells, as well as inflammation promoting cells, reducing the body’s ability to fight off infections and bugs (9).

But how does sleep affect appetite signals?

Great question.

Ghrelin and Leptin are two key hormones that regulate appetite. Ghrelin, a hormone released by the stomach, stimulates hunger, fat production and body growth. Leptin, hormone secreted by fat cells, signals fullness and stimulates energy expenditure. With healthy brain function, the two hormones work together to regulate feelings of hunger and satiety. Inadequate sleep has been found to increase ghrelin secretion, a protective mechanism to in response to increased energy expenditure from extended wakefulness (10)

One study found Ghrelin levels increased during acute sleep deprivations, while Leptin levels decreased with chronic sleep restriction. Both appetite signals were affected by short-term and long-term changes to sleep amounts. The authors concluded that studies on sleep deprived humans and rats, preferred high energy-dense foods, as a result of increased hunger and energy expenditure. In a society where junk food can be obtained from the nearest store (or through food delivery), it’s easy enough to overindulge on junk food, contributing to obesity and weight gain. Light sleepers may also have extended time to overeat, such as late night snacking (11).

Generally, with my patients, there’s underlying factors that negatively affect their sleep, appetite and weight. A stressful lifestyle from work demands, relationships, family and/or financial situations, may cause a person to think whilst in bed, OR chronic pain and inflammation may disrupt a proper night’s rest OR being overly stimulated by electronics close to bedtime OR overstimulated by the use of caffeine OR a person’s poor sleeping habits influence their snacking frequency and choices. These are common reasons why someone may have poor sleep, which can also be a combination. 


Find the root cause of what is keeping you from a restful night of sleep, and address it. You could be counting calories, or committed to exercising, but with lack of quality sleep, you’re less likely to achieve the results you want.

Here are some general ways to improve sleep hygiene:

  • Dark, cool, quite room (use earplugs if needed)
  • Turn off electronics or other bright lights close to bedtime
  • Wake up and go to bed the same time
  • Exercise 20-30minutes a day (walking, an activity you enjoy, grab a friend)
  • Try to get some natural sunlight (eat outside, go for a walk)
  • Try not to nap during the day, as this recharges your “battery”. However, this may be different for shift workers.
  • Caffeine free after 2-3pm. If not consuming excessive amounts of caffeine but can’t unwind before bed, there may be a problem with liver detoxification or hormones. Natural herbs can help with this.
  • Is it stress related? Trying meditation, mindfulness practice, exercise to manage stress

For shift workers, it can be a challenge to implement a routine, but it is possible to work around a work schedule. Some may need supportive herbs to help regulate hormones and neurotransmitters.

If you suffer from poor sleep habits, chronic insomnia or require tailored advice, for example: medical conditions for GERD, needing to speak to a counsellor, practising mindfulness or honing in on nutrition; give reception a call to see what services will best fit your needs.

  1. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-Sleep
  2. Bosy-Westphal A, Hinrichs S, Jauch-Chara K, Hitze B, Later W, Wilms B, Settler U, Peters A, Kiosz D, Müller MJ. Influence of partial sleep deprivation on energy balance and insulin sensitivity in healthy women. Obesity facts. 2008;1(5):266-73.
  3. Schmid SM, Hallschmid M, JAUCH‐CHARA KA, Born JA, Schultes B. A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal‐weight healthy men. Journal of sleep research. 2008 Sep 1;17(3):331-4.
  1. Kruger AK, Reither EN, Peppard PE, Krueger PM, Hale L. Do sleep-deprived adolescents make less-healthy food choices?. British Journal of Nutrition. 2014 May;111(10):1898-904.
  1. https://sleepdisorders.sleepfoundation.org/chapter-1-normal-sleep/the-physiology-of-sleep-the-endocrine-system-sleep/
  1. Longordo F, Kopp C, Lüthi A. Consequences of sleep deprivation on neurotransmitter receptor expression and function. European Journal of Neuroscience. 2009 May 1;29(9):1810-9.
  2. Hurtado-Alvarado G, Pavón L, Castillo-García SA, Hernández ME, Domínguez-Salazar E, Velázquez-Moctezuma J, Gómez-González B. Sleep loss as a factor to induce
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