Is a lack of sleep associated with weight gain and obesity?
Individuals displaying short sleep durations have been linked with higher BMI’s and risk of obesity (2). Sleep requirements typically vary, but research suggests that weight gain is associated with less than 7 hours of sleep per night (3).
For example, one study allowed participants just 5 hours of sleep a night for 5 nights. It was found subjects consumed additional calories during this period and gained 0.82kg (1.8lb) over the 5 days (4). Although a lack of sleep is generally associated with weight gain, it is not considered the single causing factor. Typically, a calorie surplus will cause weight gain and a calorie deficit will cause weight loss.
Can a lack of sleep affect your metabolism?
Your resting metabolic rate (RMR) is the number of calories your body burns at rest. One study found that sleep restriction resulted in a decreased RMR in healthy adults, which was attributed to the body attempting to ‘conserve energy’ (5, 6). If you burn fewer calories per day at rest, then you are more likely to gain weight.
Is appetite affected by sleep duration?
When you have had insufficient sleep the satiety hormone leptin decreases, while the hunger-stimulating hormone ghrelin increases (7, 8). These hormonal changes can increase appetite by about 15%, making your diet even more challenging to adhere too! (9). In one study men who slept four hours ate on average 559 more calories the next day compared to when they were allowed 8 hours’ sleep (10).
Can a lack of sleep increase insulin resistance?
Insulin is a hormone that helps control blood sugar levels by transporting sugar from the bloodstream into your body cells to be used as energy. When cells begin to become resistant to insulin, a greater amount of sugar remains in the bloodstream which means more insulin needs to be produced to compensate. Insulin resistance is associated with type 2 diabetes and weight gain (10).
In one study, men who slept four hours for six consecutive nights saw their bodies ability to lower blood sugar decrease by 40% (11). This study suggests that just six nights of poor sleep can increase insulin resistance.
How much sleep should you be getting a night?
Sleep duration requirements vary depending on age and from person to person. However, in a recent study carried out by The National Sleep Foundation, it was suggested adults should be getting 7-9 hours’ sleep a night (12). We know this can be tough to stick to at times. However, by sleeping these suggested hours you are giving yourself the best possible chance of achieving your weight loss goals!
Tips for a better night’s sleep
- Maintain a consistent sleeping schedule, even on weekends
- Turn off the lights before bed as this releases the body’s natural sleep hormone ‘melatonin’
- Avoid caffeine at least 6 hours before bed
- Optimise your bedroom temperature
- Turn off all electronics at least an hour before bed – read a book instead!
- Create a relaxing bedtime ritual, this could be a hot bath or shower