Did you know that chronically poor sleep can result in weight gain and an increased risk of type 2 diabetes?  The less someone sleeps, the higher their risk.

People who routinely sleep only 6 hours per night are 9% more likely to develop both obesity and type 2 diabetes.  People who sleep 5 hours per night have an 18% higher chance of developing both conditions.1

Poor sleep (and the associated fatigue) is often a major challenge for clients after a traumatic injury, such as a brain injury, spinal cord injury or complex orthopaedic trauma.

There are often numerous factors contributing to poor sleep in these clients, such as:

• the development of sleep apnoea (either due to weight gain or as a consequence of a brain injury)
• lack of consistent sleep/wake times
• insufficient morning sunlight exposure
• too much screen time just before bed
• poor sleep hygiene
• unmanaged pain
• excessive caffeine intake (or caffeine consumed late in the day)
• alcohol consumption (even small amounts can impair sleep) and/or
• nutrient deficiencies (such as vitamin D, zinc, iron and magnesium) which can negatively impact melatonin production

While poor sleep can exacerbate weight gain, clients recovering from a major trauma frequently struggle with post-injury weight gain for other reasons as well.  This is often due to a combination of the following:

• metabolic changes as a result of losing significant amounts of muscle mass
• not being aware of how much they need to reduce their calorie intake to offset these metabolic changes
• medication side effects
• mobility issues
• significantly reduced levels of physical activity
• comfort eating and/or
• reduced mental capacity (in some situations).

So how exactly does poor sleep lead to weight gain?

1. Hormonal changes (1, 2, 3, 4)

Sleep deprivation increases levels of the hunger hormone ghrelin and reduces levels of the satiety hormones leptin, GLP-1, and PYY. As a result, people will typically eat an additional 250-500 calories per day.

2. Increased hedonic eating (1, 2, 3, 4)

Sleep-deprived people are more likely to eat for pleasure (hedonic eating) rather than hunger (homeostatic eating). Pleasure eating often results in cravings for high-calorie, high-fat and/or carbohydrate-rich foods—particularly snacks and foods with lower nutritional value. The physiological stress of insomnia can further promote cravings and overeating.

Less time asleep also means more waking hours available for eating.

3. Changes to insulin sensitivity (2, 4)

Even one night of partial sleep deprivation can raise blood glucose levels and five nights can decrease whole body insulin sensitivity by up to 25%.  This can ultimately increase the risk of type 2 diabetes.

4. Metabolic changes (1, 4)

Poor sleep decreases energy expenditure, largely because fatigue reduces motivation for physical activity and/or reduces exercise effort (and calorie burn).

5. Side effect of medication (5)

Mirtazapine and quetiapine are sometimes prescribed to help people sleep, but these medications can promote weight gain by increasing appetite and food cravings (which are side effects of these medications).

What about sleep apnoea? (6, 8)

The weight gain from poor sleep can lead to obstructive sleep apnoea (OSA).  In fact, 31.5% of obese individuals will have OSA.  Sleep apnoea can then worsen the quality of someone’s sleep which then further increases the risk of obesity and weight gain.  It’s a vicious cycle.

The mechanisms for weight gain due to OSA are similar to what is described above, except OSA has a slightly different impact on leptin.

• OSA is linked to higher levels of ghrelin which makes people more hungry.  This increases both food intake and cravings for high-calorie foods.
• People with OSA actually tend to have MORE circulating leptin in their body, but they tend to be more resistant to leptin.  This means they don’t get the “I’m full” (satiety) signals the way they should.
• People with OSA are less likely to be physically active due to daytime sleepiness.
• The intermittent hypoxia and fragmented sleep from OSA can increase stress hormones, oxidative stress and inflammation.  All of this can make insulin resistance worse and can drive up glucose levels (independent of obesity).

For all of the reasons above, it is essential that dietitians who are supporting clients with weight management (and diabetes management), ask about a person’s sleep duration, sleep quality and risk of sleep apnoea.  Weight loss strategies won’t be nearly as effective if poor sleep continues.  Clients may need the dietitian to ask the GP or case manager to refer them for a sleep assessment.  Additionally, support from Occupational Therapy and Neuropsychology may be needed to discuss sleep/wake routines and sleep hygiene.

For more information or to refer a case management or litigation client for a comprehensive dietetic assessment, private blood tests and an associated report, please contact Specialist Nutrition Rehab at 0121 384 7087 or info@specialistnutritionrehab.co.uk.

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