The Missing Links to Successful Weight Loss

Written By: Alex Allegro (Accredited Exercise Physiologist)

It is well documented in the scientific literature that exercise and diet are the two primary drivers of weight loss for most of the world’s population.

Overwhelming evidence supports our Exercise Physiologists recommendations that in order to lose weight, you need to be consume less ‘energy’ (i.e food), than what your body requires to maintain normal function, otherwise known as a calorie deficit.

How does this work? In lay terms, as our body isn’t receiving enough energy from food, it needs to dip into out fat stores to utilise as fuel for function, therefore resulting in weight loss.

Sounds simple right? Yes and no.

When losing weight in an effective and healthy manner, it encompasses a large lifestyle change for most individuals.

Losing weight is more than just the number on the scales – the way you look, act, feel and function are all improved with positive lifestyle changes.

The lifestyle changes which have the most impact are the improvements you make to your exercise regimes and daily nutritional habits.

Whilst many people turn to extreme diets and supplements to fast track their results, they often neglect the importance of some of the fundamentals to human function and health: sleep, hydration, and stress management.

Image Source: Womens Health Mag

The Importance of Sleep for Weight Loss

Among the literature, it is widely concluded globally that sleep deprivation has clear links with people who are suffering from being overweight or obesity (1-5). Whilst only one piece of the puzzle, its impacts cannot go unnoticed.

So how does sleep play such an important role?

When our body is running off a few hours less sleep, our body tends to be playing catch up for the rest of the day. Often feeling tired and lethargic, we gravitate towards the most convenient “pick me up” foods we can find. These are often sugary energy drinks, soft drinks or foods with low nutritional value that help us to feel good.

When our body is sleep deprived, it is in a state of stress, hence why the “feel good” foods are often consumed, which may not be the best choice for helping our waistlines.

The state of stress can be seen hormonally through elevated cortisol levels (the stress hormone).

When cortisol is elevated, our body is more likely to store the foods we eat as fat (1-5). Already we can see the importance of managing our sleep to reduce the production of cortisol within our system.

Additionally, when sleep deprived, research has shown there to be alterations in our leptin and ghrelin hormones, which are essentially responsible for feelings of hunger and satiety.

With our body finding it harder to send signals to our brain that we are full and that we are still hungry – resulting in overeating.

Moreover, those who are in a state of constant stress are more likely to breakdown lean muscle tissue rather than dip into their fat stores for energy (6).

A study conducted in 2016 showed that when individuals get ~4-5 hours of sleep per night are compared to individuals who achieved ~8 hours of sleep per night, they experienced a greater breakdown and loss of lean muscle tissue rather than body fat, even if total weight loss was the same across both groups (6).

“Although weight loss was still being achieved by both groups, the group with ~8 hours of sleep per night had greater preservation of lean muscle tissue and overall improved metabolic health as a result.

Now whilst sleep deprivation itself can cause the body to be in a state of stress, other life stresses can have similar impacts upon our mood, health and metabolic health. So thus being important to develop effective stress management techniques to help reduce the associated health consequences.”

Importance of Hydration for Weight Loss

Previous research has documented the extensive importance of being adequately hydrated from optimal cell function, immune health, energy levels and improved mental clarity/cognition.

Whilst water intake may not have a direct correlation with a reduction in body fat, it is one piece of the puzzle in achieving the healthiest versions of ourselves.

We often hear that our body is made up of up 60% of water – but why is this important?

As mentioned previously, there are many impacts on our overall function because of dehydration.

Two major consequences of dehydration are a reduction in energy levels and a reduction in cognitive capacity.

The reductions in energy levels may be detrimental as if we are feeling lethargic, we are less likely to get moving and complete physical activity – resulting in less “energy” being expended for weight loss.

Similarly, the reduced mental sharpness we may experience through being dehydrated can lead to poor decision making with food.  This can lead to poor choices with food intake and often results in us selecting foods which are ‘stimulants’ in the form of processed carbohydrates, sugars and caffeine.   Consumption of these food types lead to fat gain.

Whilst a restrictive diet is not always encouraged, minimising foods that should be eaten in moderation is key for your health.

Our team of Accredited Exercise Physiologists are passionate about supporting client through lifestyle changes to reduce fat to ensure our clients feel great and reduce their risk of chronic disease.

Contact our Exercise Physiology team at Inspire Exercise Physiology today on 9857 3007 to discuss how we can support your health.


  1. Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD. Insufficient sleep undermines dietary efforts to reduce adiposity. Annals of internal medicine. 2010 Oct 5;153(7):435-41.
  2. Hewagalamulage SD, Lee TK, Clarke IJ, Henry BA. Stress, cortisol, and obesity: a role for cortisol responsiveness in identifying individuals prone to obesity. Domestic animal endocrinology. 2016 Jul 1;56:S112-20.
  3. Vicennati V, Pasqui F, Cavazza C, Pagotto U, Pasquali R. Stress‐related development of obesity and cortisol in women. Obesity. 2009 Sep;17(9):1678-83.
  4. Geiker NR, Astrup A, Hjorth MF, Sjödin A, Pijls L, Markus CR. Does stress influence sleep patterns, food intake, weight gain, abdominal obesity and weight loss interventions and vice versa?. Obesity Reviews. 2018 Jan;19(1):81-97.
  5. Reinehr T, Andler W. Cortisol and its relation to insulin resistance before and after weight loss in obese children. Hormone Research in Paediatrics. 2004;62(3):107-12.
  6. Kazakov M. Fat Loss and Lack of Sleep.