At a glance, this image taken from "Why We Sleep" By Matthew Walker, gives the impression that the less you sleep, the more obese you become.
This isn't directly true and is one of the problems with correlation-based information. Bad sleep does not DIRECTLY make you gain weight. However, there are mechanisms behind this association that can cause you to have an increased potential for weight gain.
To be clear, poor sleep doesn't make you obese, but it could make you more likely to become so.
Here are 3 potential reasons why.
1) It has been shown that impaired sleep reduces the waking basic metabolic rate (1) by around 2%. For me, this would mean around a 40 to 50 calorie difference following a single poor night's sleep. Not huge on its own, but that could mean up to 350 calories a week. (I'm not sure about the dampening effect over time because the study only show's acute sleep deprivation not chronic).
2) "A Single Night of Sleep Deprivation Increases Ghrelin Levels and Feelings of Hunger in Normal-Weight Healthy Men" I love it when the title of a study is that clear.
If you read yesterday's post on Fullness & Food Density you will already know about Ghrelin. The interesting part about this study is that leptin secretion doesn't seem to change.... A less than ideal combination.
3) There is a link between fasting blood glucose (level of glucose in the blood upon waking), sleep disruption, and obesity (3), however, it is still unclear what causes what. Raised fasting blood glucose is a trait associated with type II diabetes and is basically a sign that your body struggles with regulating insulin and glucose. Although this does not directly cause you to gain weight, it has implications with appetite and energy levels, just adding to the likelihood that you may make poor decisions when it comes to food (being hangry more often and feeling like you need a sugar fix). There is some strength to the idea that sleep disruption could be a significant contributing factor however, with obstructive sleep apnea (OSA) patients (a highly correlated issue with diabetics) having improved fasting blood glucose levels after 2 days of continuous positive airway pressure therapy (CPAP, sleeping with a mini ventilator machine to help regulate breathing)(4). Tedious links I know, but this goes with my optimistic way of thinking and adds strength to the idea of PRIORITISING SLEEP.
So take this information, organise your sleep habits, and get between 7.5-9 hours of good quality sleep a night somewhere between 9pm and 8am.
EVERY NIGHT FOR THE REST OF YOUR LIFE (optimistic I know).
If you don't, you could feel more hungry, have energy disruptions causing you to make poor decisions and your BMR could drop by 50 calories,
Not guaranteed to happen of course, but why make your life more difficult when you could just get to bed on time...