top of page

Fat Loss & Sleep!

The Importance of Sleep on your Fat Loss Journey

We all know getting enough sleep is important, and vital to help us function on a daily basis. But just how much does the quality and quantity of our sleep impact how we lose weight, store fat and burn calories.

Poor sleep has been linked to higher BMI and weight gain. A 2008 meta-analysis of short sleep duration discovered less sleep resulted in an increase in the likelihood of obesity of 89% in children and 55% in adults. A study on sleep deprivation, allowing 16 adults just 5 hours of sleep per night for 5 nights resulted in an average weight gain of 1.8lbs.

A 2010 study found that sleep deprived dieters felt hungrier, this was the result of ghrelin, our hunger hormone. Sleep deprivation elevates ghrelin levels, making you feel more hungry and reducing your energy expenditure. Without adequate amounts of sleep, your body produces less leptin, the opposite of ghrelin. Leptin helps to suppress hunger and signals fullness to the brain.

In addition, the frontal lobe of the brain helps with making decisions and also self-control. A poor night sleep results in a dulling of activity in the frontal lobe making it harder for you to avoid that chocolate bar or donut! Other research also discovered that not enough sleep actually makes you want foods higher in calories!

What happens when we consume those foods and drinks we crave? Well, large meals, high sugar content foods, alcohol, all have a negative impact on our sleep. You all know this, but what’s the reasoning behind it? During sleep, our resting heart rate (RHR) should decline to allow the body to recover. But consuming any of the above can significantly increase your resting heart rate slowing your ability to recover at night. Interestingly keeping track and measuring your RHR can be quite a reliable gauge for recovery!

Now that we’ve established why lack of sleep has a direct negative impact on fat (weight) loss, let’s discuss the other benefits of getting MORE sleep can have on your journey.

We all have those days where we are not motivated to do anything, we don’t want to leave the couch, let alone actually exercise, this is due to daytime fatigue. It’s well known that more sleep results in more motivation, faster reaction times, improved accuracy and attention, in addition to a reduction in fatigue.

Aside from losing fat, we need to be able to perform. One of the most important factors of your weight-loss journey is resistance training. Without resistance training, the likelihood of losing the muscle you have is very high. Without muscle, burning calories becomes a little harder. Fat doesn’t require energy to move, but muscle does, so it is imperative we preserve as much lean mass as possible. How does this link to sleep you ask? Well, sleep, in particular deep sleep, allows our heart to rest enabling our cells and tissues to repair. Interestingly, in order to “increase” deep sleep, you need to exercise! So get out there, start getting in some activity to improve on all aspects of your life! *NB if you have trouble sleeping, avoid activity closer to bedtime.

More indirect benefits of sleep for weight-loss include improving or having a lower affinity for getting sick. Allowing the body to fully rest and recover helps improve our immune systems preventing us from getting sick. It goes without saying, if you're sick, the chances of you exercising, or even wanting to exercise significantly decreases.

The next one is for the guys! (And believe it or not, for the girls too) A 2011 study testing the impact of sleep on testosterone discovered that cutting back on sleep, drastically reduces healthy young man’s testosterone levels. The study found that five hours of sleep decreased the subjects testosterone levels by 10-15%! Not to mention that testosterone levels in men decline by 1% to 2% each year as they age.

So circling back and linking these together;

In order to lose weight we need adequate sleep so that we don’t make bad food choices, bad food choices result in poor sleep. Poor sleep results in more bad food choices, leading to low motivation resulting in a reduced desire to exercise. Lack of exercise means less muscle or muscle wasting, which means lowered ability to burn calories, which lowers rate of weight loss. Adding alcohol to the mix further exacerbates the above, reducing sleep quality, hindering recovery and further increasing those cravings for poor food choices. In addition to this, research has shown that alcohol also negatively impacts testosterone, causing a drop in as little as 30 minutes after the consumption of an alcoholic drink. Let’s not forget our last paragraph with testosterone dropping 1-2% annually! And now we have a recipe for disaster!