7 – 9 hours of sleep per night is recommended for adults (18 – 64 years). Most well-rested adults fall asleep within 10 – 20 minutes of attempting to sleep and spend less than 30 minutes awake during the night. People with insomnia complain of poor sleep quality or insufficient amount of sleep due to difficulty initiating sleep (taking 30 minutes or more to fall asleep), difficulty maintaining sleep (spending 30 minutes or more awake during the night) or waking up too early (at least 30 minutes before planning to).3

Insomnia can affect your daytime functioning, causing extreme tiredness (fatigue), reduced motivation or energy, poor attention or concentration, irritability, daytime sleepiness, ongoing worry about sleep etc.3

Insufficient sleep duration (defined as 6 hours or less in a 24-hour period) and poor sleep quality have been linked to conditions like obesity, hypertension and diabetes.2

How insomnia or insufficient sleep leads to weight gain1,4,5

Hormones that regulate appetite
Two hormones in your body help control your appetite. Leptin is involved in the regulation of food intake and energy balance. It tells your body when you’re full (to suppress food intake) and stimulates your body to consume energy. Ghrelin stimulates appetite (telling your brain that you are hungry), fat production and body growth – leading to increased food intake and body weight. When you don’t get enough sleep, your levels of leptin drop, causing your brain to send out signals that you may be hungry (less full), even though you don’t need to eat. At the same time, your levels of ghrelin increase, so you feel hungry. The resulting hunger pangs lead you to increase your food intake.1,4,5

Insomnia also leads to increased levels of cortisol, which plays a role in increasing your desire for high fat and high sugar foods, and storing fat in your tummy (abdomen).1

Tip: Limit the amount of junk food in your house and stock up on healthy snacks. That way, if you do feel hungry, you have access to healthier food options.4

More snack time
The longer you stay awake, the more time you have to eat. Snacking throughout the day adds extra calories to your diet and can lead to weight gain.4

Tip: Before you grab a snack at night, ask yourself if you’re really hungry. If not, drink a glass of water or go for a walk to tide you over.4

Less exercise
You’re less likely to exercise because you’re too tired from not sleeping enough.4

Tip: Start moving. Moderate-intensity aerobic exercise 3 hours before bedtime can reduce the time it takes you to fall asleep, the time you spend awake at night, pre-sleep anxiety, while increasing total sleep time and sleep efficiency.1,4

How insufficient sleep or sleep depriva6on increases your risk of developing diabetes2

A sleep disorder like insomnia can increase your risk of diabetes through mechanisms like glucose intolerance, insulin resistance and changes to the levels of ghrelin and leptin in your body.2

Glucose intolerance is an umbrella term for a group of metabolic conditions that result in higher-than-normal blood glucose (sugar) levels.6

Insulin is a hormone that helps glucose reach the cells in your body, so that it can be used for energy. Insulin resistance means that your cells become resistant to the effects of insulin, and cannot use glucose from your blood, resulting in higher levels of glucose circulating in your bloodstream.7

Sleep can both raise and lower your blood glucose levels. The circadian rhythm that your body experiences every day, naturally raises blood glucose levels at night and when you sleep. These natural elevations in blood glucose levels are not a cause for concern. Restorative sleep may lower unhealthy blood glucose levels by promoting healthy systems in your body. Sleep deprivation (even over the course of just one night) increases insulin resistance, which in turn increases blood glucose levels. Sleep deprivation also increases cortisol levels, which in turn increase blood glucose levels. Over time, increased blood glucose levels, if not treated, increase your risk for pre-diabetes and Type 2 diabetes.7,8

Insufficient sleep or sleep loss decreases leptin levels and increases ghrelin levels. This hormonal disruption can lead to overeating and increase the risk of obesity and in turn, diabetes.2,7

The good news2

Successful management of insomnia can lead to improved glycaemic control (blood glucose levels), glucose tolerance and reduced risk of diabetes.


We’ve created a booklet filled with useful Dps to help you manage your insomnia9

In preparing this article, every effort has been made to provide an objective overview. The content contained in this article contains medical or health sciences information as per cited articles for public information. The content of this article has been initiated and is brought to you by Sanofi South Africa.

  1. Hargens TA, Kaleth AS, Edwards ES, et al. Association between sleep disorders, obesity, and exercise: a review. Nat Sci Sleep 2013;5:27-35.
  2. Seixas AA, Robbins R, Chung A, et al. Sleep health and diabetes: the role of sleep duration, subjective sleep, sleep disorders, and circadian rhythms on diabetes. Sleep and Health 2019;17:213-225. https://doi.org/10.1016/B978-0-12-815373-4.00017-4.
  3. Bonnet MH and Arand DL. Evaluation and diagnosis of insomnia in adults. 04 October 2022. UpToDate. Available online at https://www.uptodate.com/contents/evalua1on-and-diagnosis-of-insomnia-in-adults. [Accessed 26 June 2023].
  4. DiLonardo MJ. The connection between sleep and obesity. 07 March 2022. WebMD. Available online at https://www.webmd.com/sleepdisorders/ sleep-obesity. [Accessed 26 June 2023].
  5. Prinz P. Sleep, appetite, and obesity - What is the link? PLoS Med 2004;1(3):186-187.
  6. Olatunbosun ST. Glucose intolerance. 08 July 2020. Medscape. Available online at https://emedicine.medscape.com/article/119020-overview. [Accessed 27 June 2023].
  7. Cervoni B. The link between diabetes and insomnia. 24 March 2022. Verywellhealth. Available online at https://www.verywellhealth.com/diabetes-and-insomnia-5218041. [Accessed 27 June 2023].
  8. Pacheco D. Sleep and blood glucose levels. 16 December 2022. Available online at https://www.sleepfoundation.org/physical-health/sleep-andblood- glucose-levels. [Accessed 27 June 2023].
  9. Tips to help you overcome insomnia and get the sleep you need. Patient resource. Sanofi. MAT-ZA-2100751-1.0-07/2021.