Intuitively speaking, longer sleep seems better than shorter sleep, but does lack of sleep cause weight gain?
The material below will detail in brief the suggested mechanisms by which a lack of sleep may lead to increase in the risk of obesity and diabetes. I have taken this information from a journal article HERE – The metabolic consequences of sleep deprivation.
I’m going to begin by copying the abstract, as the abstract sums it up pretty well:
The prevalence of diabetes and obesity is increasing at an alarming rate worldwide, and the causes of this pandemic are not fully understood. ((See an article HERE on metabolic syndrome and HERE on saturated fat for a more in depth look at obesity and ill-health)). Chronic sleep curtailment is a behavior that has developed over the past 2-3 decades. Laboratory and epidemiological studies suggest that sleep loss may play a role in the increased prevalence of diabetes and/or obesity. Current data suggest the relationship between sleep restriction, weight gain, and diabetes risk may involve at least three pathways: 1. alterations in glucose metabolism; 2. upregulation of appetite; 3. decreased energy expenditure. The present article reviews the current evidence in support of these three mechanisms that might link short sleep and increased obesity and diabetes risk
What does this mean?
In simple terms, the abstract of the article suggests that part of the reason why obesity and diabetes are on the increase is because of a decrease in the number of sleeping hours people are getting, on average, per night. In addition, there have been various hypotheses suggested as to why this might be the case. Specifically, 3 suggestions have been put forward:
1) Cutting sleep short leads to altered, and impaired, blood sugar regulation the following day. For instance, for the same meal there may be a greater blood sugar response in the body, and a reduced sensitivity to insulin (after a short nights sleep). This is perhaps a ‘transient’ process (very short term, which disappears), and one night of poor sleep may not have any lasting ‘damage’. Alternatively, this may be ‘cumulative’, and all those hours of sleep missed begin to ‘add up’ at some point. Ultimately, after a poor nights’ sleep, our blood sugar levels likely rise to a greater degree after eating than perhaps it would have done had we slept well
2) Cutting sleep short appears to lead to an increase in appetite, such that an individual may consume more calories after a poor nights sleep as opposed to when they got sufficient sleep. This is most probably due to hormonal changes, and levels not being what/where they should. In addition, it is also possible that after a poor nights sleep one chooses more calorie-dense foods, making over-consumption of calories more likely.
3) Cutting sleep short may decrease one’s energy expenditure the following day i.e. we might burn fewer calories after a poor nights sleep, such that our energy balance remains positive (i.e. we accumulate weight over time as we’re expending less calories than we’re burning).
Limitations on the studies done thus far (and here’s another quote from the article):
One important limitation of all these epidemiologic studies is that they all relied on self-reported measures of sleep.
Self-reported measures of sleep are perhaps not the most accurate, so we must interpret the findings with caution. More intervention studies are required as, thus far, the majority of studies appear to be by association. For instance, it may be possible that becoming overweight leads to poor sleep, and not the other way round, as has been suggested. However, the alternative: that you are likely to eat more, move around less and regulate blood sugar levels worse after a good/sufficient nights’ sleep appears unlikely.
Read the article HERE for ways to improve the time it takes to fall asleep, or the quality of your sleep
Take home message
Does lack of sleep cause weight gain? Not necessarily, no. If you miss out on a few hours of sleep, you won’t wake up fatter. However, other changes may occur through slight but chronic sleep curtailment that make weight maintenance less likely and/or make you more susceptible to weight gain. These changes tend to be metabolic or hormonal in nature.
Sleeping more than 7 hours per night (7-9) would be recommended, given the association between sleep curtailment and obesity/diabetes. Also, younger individuals require more sleep. Very slight but consistent sleep loss (perhaps 6 hours or less) may affect health – through a number of different pathways – that make obesity and diabetes more likely. Don’t be in the category: 6 hours or less