Healthy Sleep

Sleep Yourself Slim, as Told by a Lifestyle Medicine Physician

We all know that lack of sleep can affect our bodies mentally. But did you know that sleep deprivation can also cause changes to our physical bodies too?

We believe all bodies are beautiful, but if you’re trying to maintain a healthy weight, your daily snooze may be as important as your daily meals and exercise. We spoke with Dr Lucy Burns, a Lifestyle Medicine Physician in Victoria, to find out why sleep may be the most overlooked aspect of your weight management plan.  

We need between 7 and 8 hours of sleep per night for our body to thrive. Anything less is sleep deprivation.

Our society does not value sleep. Currently, most of us view sleep as something we fit in at the end of the day. In fact, people who “survive’ on little sleep are often lauded as special or heroic. Google “successful people who barely sleep”, and you will find a list of CEO’s, politicians, etc. who claim to only have 4 hours sleep a night. Apparently, this is something to aspire to. The term the “sleepless elite” is used, and they are considered lucky.

What is missing from this picture is all the wonderful things that happen to our bodies and brains while we are asleep.  This is where the magic happens.

The association between lack of sleep and obesity is clear. Let me explain why.

The first thing to understand is, what is sleep?

All the hormones of the body affect all the other hormones of the body. Our hormonal system (also called the Endocrine system) is a tightly controlled, finely tuned, and intricate operation. It is like an orchestra. Every hormonal instrument working together to make the orchestral piece work. If one hormonal instrument is off, it can tune the whole symphony into disarray.  The conductor of this great hormonal symphony is our circadian rhythm. The internal biological clock set to the Earth’s 24-hour night/day cycle.

Sleep is a hormonal process that involves both melatonin and cortisol. 

Melatonin is our going-to-sleep hormone and cortisol is our waking-up hormone. Remember cortisol; we’ll be coming back to it. 

Effective sleep occurs when these hormones are in balance, and we listen to them!

Did you know that humans are the only animals to restrict their sleep voluntarily?

No dogs are staying awake to watch Netflix. Cats are not sleep deprived because they were reading the last few chapters of a super-exciting book. We don’t see sheep, monkeys or butterflies wide awake, playing computer games overnight. Nope, only humans do this. Humans restrict their sleep. All. The. Time.

Sleep Can Prevent Weight Gain

Sleep has a powerful connection to metabolism.  Sleep affects the hormones that regulate appetite and the body’s use of blood sugar and insulin.

Insulin is the master metabolic hormone. It keeps blood glucose balanced and stops fat breakdown.

Sleep deprivation worsens insulin resistance. Insulin resistance means the body can’t use insulin effectively. It responds by making more and more of it - buckets of the stuff. Elevated insulin causes our body to become a fat storage machine.

There are a myriad of studies confirming that reduced sleep increases insulin resistance.

Sleep deprivation also increases the production of cortisol, the stress hormone. This is also our waking up hormone. Suddenly, we are in the cycle of not having enough sleep but having too much waking up hormone - the so-called over-tired syndrome. 

Excessive cortisol increases blood sugar and increases insulin resistance, making insulin even higher. More fat storage ensues.

While we are sleeping, our body releases other hormones into the bloodstream that regulate our hunger. These are Ghrelin and Leptin.

Ghrelin is our hunger hormone. This rises with sleep deprivation, and we are hungrier.

Leptin is our satiety (fullness) hormone which falls with less sleep. This means we don’t feel full.

So when we don't get enough sleep, we are tired, hungry and not full - a recipe for over-eating. Remember our body's hormonal profile has also changed due to sleep reduction.

We are now an over-eating super-efficient fat storage machine.

But with good sleep, our metabolic hormones improve.

We are less stressed.
We are less hungry.
We feel fuller.
We are no longer a fat storage machine.

All you have to do is go to bed and go to sleep. 

So yes, you truly can sleep yourself slim. 

About the author

Dr Lucy Burns speaks at conferences for doctors on weight management as well as events for the general public. Her online learning platform and role as a Lifestyle Medicine Physician helps educate her patients on successful methods for weight management.