Lack of sleep and weight gain
A lack of sleep does a few things to your body that can make you gain weight.
The first one is that it can lead to bad dietary choices by enhancing your hunger levels with the elevated release of the hunger hormone ghrelin and the suppression of leptin, the primary hormone that decreases your appetite.
Now we know what you're thinking – that you have willpower and will avoid those bad dietary choices – but that isn't the end: poor sleep can also slow down your metabolism, meaning you burn fewer calories.
That means even if you eat well and move around, your body won't burn as many calories as it would with a good night's sleep.
Less sleep also means more tiredness and fatigue, making you less willing to stay active and reduce your calorie burn through less activity.
Of course, there are ways to counteract the effect on your metabolism, such as exercise, but sleep is the key to keeping off the pounds (a high-quality mattress goes a long way to ensuring optimal rest).
We provide more colour below.
Sleep and appetite
Sleep and appetite are connected through a complex interplay of hormones, most notably ghrelin and leptin, with these two hormones playing crucial roles in regulating hunger, satiety, and overall energy balance in your body.
Ghrelin is the "hunger hormone" that stimulates appetite. When sleep is insufficient, ghrelin levels tend to increase, leading to heightened feelings of hunger and a greater desire to eat, a hormonal shift that can result in increased calorie intake.
On the other hand, leptin, known as the "satiety hormone," is produced by fat cells and signals fullness to the brain – a lack of leptin means you’ll eat more to feel satisfied.
Unlike ghrelin, leptin levels decrease with inadequate sleep, diminishing feelings of fullness and satisfaction after eating.
So, a hormone imbalance creates a perfect storm for weight gain, leading to bad dietary choices and greater calorie intake.
Sleep and calorie burn
A lack of sleep can slow your metabolic rate and reduce your calorie burn, making it easier to gain weight even when dieting.
The slowdown in calorie burn is partly due to hormonal changes. Lack of sleep affects the production and regulation of hormones like cortisol and insulin.
Cortisol is a stress hormone that increases with sleep deprivation, leading to increased appetite and potential insulin resistance. Insulin resistance can make it harder for the body to use glucose effectively, potentially slowing metabolism.
Sleep deprivation also decreases the body's resting metabolic rate (RMR) -- RMR is the number of calories burned by the body while at rest, accounting for a significant portion of daily energy expenditure.
Lower energy expenditure
When you're tired, you will be less active, burning fewer calories during the day.
Think about it like this – taking the elevator instead of the stairs, driving to the shops instead of walking, lying on the sofa instead of playing football with your kid – these things are a welcome relief when you haven't slept.
Moving around more will help you counteract the issue, but you'll be more prone to giving up and likely crash early.
Summing up
A lack of sleep can make you gain weight by:
- Increasing your appetite and reducing feelings of fullness after eating
- Slashing your calorie burn by lowering your resting metabolism rate
- Further reducing your calorie burn by reducing your physical activity levels
Of course, each has a solution when you haven't slept – eat less, eat well, and keep moving to keep the pounds at bay. Have some willpower, and you'll do fine.