Can my sleep affect my weight?

There is significant evidence that adequate, quality sleep helps maintain healthy hormone balances that affect appetite and weight management:  Studies have consistently shown a link between sleep deprivation and weight gain. One study found that adults who slept less than 6 hours per night were more likely to be obese than those who slept 7-8 hours per night. Another study found that sleep deprivation increased the risk of obesity by 55%.

In practice there is more than one mechanism at play whereby our sleep can affect our appetite and weight.

  1. Hormone Balance

Sleep regulates the key hunger hormones ghrelin and leptin.  Leptin is a hormone that signals satiety, telling us when we’re full. Sleep deprivation reduces leptin production, making us feel hungrier and more likely to overeat.

Another hormone, ghrelin stimulates appetite. Sleep deprivation increases our ghrelin levels, further enhancing our urge to eat.

Cortisol, growth hormone and testosterone levels are also disrupted by poor sleep and can have adverse effects on weight.

Sleep loss is also associated with higher cortisol levels. Cortisol is involved in regulating metabolism and stress responses. High levels of cortisol disrupt the natural circadian rhythms and promote fat storage rather than fat burning.  Chronic high cortisol levels may contribute to increased fat storage, particularly in the abdominal area.

Growth hormone is produced during deep slow wave sleep. This hormone supports cell repair, muscle growth and repair and protein synthesis. Reduced sleep leads to lower availability of this key hormone and impacts our ability to recover while we sleep.

Testosterone production and regulation also requires sufficient deep sleep cycles. Low testosterone can impact many biological processes including fat distribution and body composition.

Finally, Insulin sensitivity. Sleep plays a crucial role in maintaining insulin sensitivity. Poor sleep has been linked to insulin resistance, which can contribute to the development of type 2 diabetes and weight gain.  When the body becomes less responsive to insulin, it may have difficulty regulating blood sugar levels, leading to increased fat storage.

  1. Impact on Physical Activity

Lack of sleep can lead to fatigue and reduced motivation for physical activity. This, in turn, can contribute to weight gain or difficulty in maintaining a healthy weight.  Regular physical activity is an essential component of weight management, and its disruption due to poor sleep can have implications for overall health.

  1. Metabolic rate

Sleep also influences the body’s metabolic rate, which is the rate at which the body burns calories at rest. Insufficient sleep has been associated with a slower metabolic rate, potentially affecting energy expenditure and contributing to weight gain.

In summary, multiple studies show that short sleep duration is linked with an increased risk for weight gain, obesity, and a reduced ability to lose weight as a consequence of inhibiting the metabolic rate and disrupting the hormone balance.  Thus, optimising sleep duration and quality supports healthy balances of ghrelin, leptin, cortisol, growth hormone, testosterone and normalises insulin sensitivity that together help regulate appetite, stress levels, growth and metabolism related to weight management.

To promote better weight management and overall health, prioritise adequate sleep. Aim for 7-9 hours of quality sleep each night. Establish a regular sleep schedule, create a relaxing bedtime routine, and avoid caffeine and alcohol before bed. Engage in regular physical activity, but avoid strenuous exercise close to bedtime. If you have persistent sleep problems, consult a doctor to rule out underlying medical conditions. By prioritising quality sleep, you can optimise your hormone balance, enhance your metabolism, and support healthy weight management. Read more here.  Tips to help you sleep well.