Having discussed common sleep disorders and the possible causes behind them, it is apparent that resorting misguidedly to a sleep aid such as alcohol to fall asleep is not the answer. 

There are several factors that impact sleep, and vice versa; we turn the lens on the intersection of sleep habits, nutrition and exercise in this piece.

What happens when you eat too close to bedtime?

Sleep expert Matthew Walker advises(1) cutting off all eating at least three hours before bed. This is primarily because you’re more likely to have acid reflux and other digestive issues when you lie down right after a meal. 

Plus – after visiting how melatonin is tied to our sleep cycle in this article – it’s worth noting that biologically, when the sun sets and your melatonin levels go up, you naturally become more insulin resistant(2). 

Simply put-

If you’re eating after sundown, when you’re less insulin sensitive, this can increase the risk of developing conditions like hypertension, obesity and type 2 diabetes. 

Also, you need to drop your core body temperature by a couple of degrees Fahrenheit to fall asleep and stay asleep – that’s why it’s easier to do this in a cool room. Even if you do have a bite to eat right before bedtime, try not to have simple carbohydrates, such as a bowl of cereal, because it can raise your core body temperature and keep you up longer.  

How is appetite affected by our sleep quality? 

When you’ve been up all night, you might notice a tendency to eat more, and to also derive less satisfaction from your food. We might just be the only species that voluntarily deprives itself of sleep; in the wild, this only generally occurs when there’s a shortage of food and animals are starving. 

So when you’re sleep deprived, the brain thinks that you’re under conditions of starvation. A cascade of hormones is released that changes your appetite profile(3) – this fake signal indicating starvation increases ghrelin (which is why your appetite increases) and suppresses a hormone called leptin (which makes you feel full).

Sleep expert Matthew Walker says, “Eating more, wanting to exercise less – you’re burning fewer calories. That is why we’re starting to understand part of the sleep-dependent obesogenic equation.”

If you’re interested in how sleep is affected by fasting and time-restricted eating, here’s some further reading. 

What happens when you’re dieting while sleep-deprived?

The study ‘Insufficient sleep undermines dietary efforts to reduce adiposity’(4) showed that when one has not had sufficient sleep (six hours or less), dieting was much less effective in terms of fat loss. This signals a metabolic inefficiency. 70% of what is lost was from lean muscle mass; your body clings on to fat when you’re underslept, likely because of the high levels of cortisol and insulin. 

When you’re sleep deprived and dieting, there are several changes in your body – inferior fuel partitioning, hyperinsulinemia, impaired glucose disposal and a tendency to crave more junk food. Physician Peter Attia puts it in a way that most of us can probably relate to, “I’m at my worst when I am sleep deprived. It’s so hard to avoid junk food. Whereas probably the single greatest tool in my arsenal to eat well (and) to sleep well.”

Does sleep deprivation impact insulin resistance?

We’ve elaborated on how insulin resistance works in this piece. This University of Chicago study(5) demonstrates how, when subjects got four hours of sleep for two weeks, their ability to store glucose in their muscles dropped by 50%. After just a week of sleep deprivation, these healthy subjects were looking pre-diabetic. 

With sleep deprivation, not only do the β cells in your pancreas become insensitive to a spike in blood glucose, the tissues also become insensitive to the signal of insulin. The bottom line is that the majority of glucose is stored in the muscles and liver, so if the body cannot use that glucose, it’s a problem. 

Simply put-

Lifestyle factors like sleep deprivation may thus lead to insulin resistance which in turn can lead to a whole host of chronic lifestyle issues and diseases such as PCOS, hypertension, obesity, inflammatory and vascular conditions.

Want to dig a little deeper into the matter? This study shows how insulin signaling is impaired.  

What is the connection between sleep deprivation and exercise? 

With exercise and sleep, it’s very much a two-way street. 

Exercising early in the day is a great tool to promote sleep, and sufficient sleep improves exercise. When you’re well-rested, you’re more motivated to do anything, especially physical exercise – and your exercise performance improves as well. Your peak muscle strength increases, the likelihood of injury drops considerably and the time it takes to reach physical exhaustion increases. Even your ability to sweat and respire improves when you’ve slept well!

That said, it is advisable not to exercise within two hours of your bedtime; exercise increases your core body temperature and keeps you up for longer, in addition to causing a hormonal change.  

All in all, sleeping well comes with a host of benefits across the areas of nutrition, weight loss and sleep. Don’t lose hope if you’ve spent many years sleep-deprived already; just as those with conditions such as Type 2 Diabetes can improve their condition with changes to their diet, exercise and lifestyle – you can do the same with sleep as well. 

Here are a few tips to sleep better and join us in launching an enquiry into whether technology can provide sleep solutions. Remember – it’s never too late to make better choices to do with your sleep cycle and work on getting enough and better-quality sleep.