Hormones And Weight Loss/Gain

Hormones And Weight Loss/Gain

It’s not uncommon to hear from voices in the health and fitness community that hormones are more important than calorie control when it comes to weight loss. However, is this true?

Energy Balance

Our bodies require fuel to stay alive and carry out the various activities we engage in every day. This fuel comes from the food we eat. We measure the energy in foods, as well as the energy we expend through activity and other bodily functions, using kilocalories (typically just referred to calories). When our bodies take in more energy than we need for our level of activity, it does this remarkable thing where it stores the excess for later use. It’s quite annoying, but it really is a beautiful thing. If we expend more energy than the food we take in provides, our bodies must get that energy from somewhere and so it taps into it’s fat stores. This is the basic principle of energy balance.


So, if energy balance is the key to weight loss/gain, do hormones have any effect? Absolutely! Energy balance and hormones work together. Hormones can impact a variety of functions within the body but it still ultimately comes back to energy balance as far as fat loss/gain is concerned.

Energy In

There are several hormones that play a significant role on our overall food intake. These hormones primarily impact hunger and satiety – our appetite. It should be clear just from that simple description how these can play a role on how much food we take in each day. If our appetite is not suppressed when we eat, or if our body is sending hunger signals to our brain, it makes it much more difficult to adhere to our calorie intake targets.

While there are others, two of the main hormones in this area are ghrelin and leptin. Ghrelin is the “hunger hormone” which comes from the gut and is typically suppressed when we have food in our stomach. Leptin is the “satiety” hormone. Both of these hormones (and others) work together to help us know when to seek out food and when we don’t need any additional food. If these hormones are not controlled or if our body becomes less sensitive to the effects of these hormones, we can struggle with hunger. Cleary, you can see how this could impact the energy intake side of the equation.

Energy Out

The thyroid is a gland and part of its job is to regulate the energy out part of the equation – the calories we burn. When thyroid hormones are impacted in one way or another, it can significantly impact the out portion of the equation by causing us to burn fewer calories (hypothyroid), or more calories (hyperthyroid). If our body is burning fewer calories this makes weight gain much easier and if it’s burning more than normal, it can cause unhealthy levels of weight loss. Fortunately, if you are someone with thyroid-related issues (Hashimoto’s, hypothyroid, etc.), properly balancing medications will typically level the playing field making it less of a factor.

Where Fat Is Stored

Cortisol is a hormone we hear of quite often usually in conversations related to stress. It does not prevent fat loss. However, it can have an impact on where fat is stored within the body and can impact the number on the scale (not the same as body fat) by affecting water retention. Testosterone and estrogen levels may also impact how energy is used for building muscle or storage as fat. Without going into a lot of detail, my point is that there are some hormones that don’t directly impact the energy in/out equation, but they do impact how that energy is utilized in the body which can impact body fat stores in various ways.


The main takeaway from this very short treatment of this subject is simple: it’s not just hormones and it’s not just calories. It’s unfortunate that many in the health and fitness world create these false dichotomies rather than see each simply as contributing factors. Energy balance is at the foundation of a proper understanding of fat loss/gain and should be the priority when it comes to putting a plan into action. However, there are numerous factors that contribute to the energy in and energy out portions of the equation which is why there should never be a one-size-fits-all approach when it comes to nutrition.