WHAT HAPPENS TO THE BODY DURING A YO-YO DIET CYCLE?
On our 4Q Fact Check IGTV, we gave an overview of the effects of yo-yo dieting on the body and explained the importance of breaking free from the vicious cycle. Here on the blog, we are going to dive a little deeper into the science behind it all.
Typically, when clients want to lose “weight” they want to lose fat, but unfortunately many of the diets out there don’t take body composition into consideration. While you may see the number on the scale drop, that number could reflect significant water and muscle loss instead of fat.
Why is that? What’s going on in the body?
The ability to lose a large amount of weight within the first few weeks on an extreme diet is in large part due to the fact that water weight comes off relatively quickly and muscle weighs more than fat.
We lose water weight because as we limit intake, particularly carbs, and increase exercise, our body relies on glycogen (stored glucose/sugars) for energy. Glycogen holds onto water, so as soon as we use up our glycogen stores, substantial water weight is released, which causes the number on the scale to drop.
We lose muscle because low-calorie diets may result in a protein deficit, which can lead to a breakdown of muscle. Our body needs protein to function (think: enzymes for chemical reactions, structures for cell membranes, amino acids for DNA replication, etc.) and without adequate dietary protein, the body breaks down muscle to supply the protein required for all those bodily functions.
Why is it such a big deal to lose muscle?
Aside from giving us a toned, lean look, muscle provides many systemic benefits to the body.
Muscle reduces inflammation.
Muscles contain myokines, which are anti-inflammatory and immunoprotective proteins that communicate between the muscle and other organs. Myokines are induced by exercise and, when released, create an anti-inflammatory environment in the body.
Muscle improves bone health.
Since muscle surrounds our bones, the anti-inflammatory functions of the aforementioned myokines help increase bone density and prevent osteoporosis. Bone density is also preserved with the physical activity of muscle contraction and gravity on the bone (i.e. weight bearing exercise). A lack of these stimuli leads to increased risk of bone resorption. With cycling diets, the fluctuations of weight in combination with the loss of lean muscle mass can speed up the process of bone loss and further lead to bone fragility.
Muscle mitigates the natural muscle loss that come with age.
As we age, we naturally experience muscle loss known as sarcopenia. The rate of muscle protein synthesis is reported to be 30% less in elderly individuals, so for those who are 50+ and trying to lose weight, it is especially important to maintain proper muscle mass so as not to exacerbate the effects of sarcopenia.
Muscle speeds up the metabolism.
Muscle directly accelerates our resting metabolic rate — the rate at which our body burns calories when we are in a resting state. Even while at rest, our body is working hard to support breathing, circulate blood, regulate organ functions, and perform basic neurological processes. This resting state makes up the majority of our calories burned in a day, and our muscles play the largest role in keeping up the metabolic rate in this state. Therefore, if we lose muscle, we are slowing down our resting metabolic rate, making it more difficult to burn calories and lose weight. On the other hand, the more muscle we have, the faster the metabolism will be, and the easier it will be to achieve our weight loss goals!
Now that we’ve established that muscle loss is undesirable, let’s revisit that yo-yo diet cycle to see how this all plays out.
We’ve gone on the diet and gotten to our goal weight, but because the diet is so extreme, we slowly loosen the reigns. This reintroduction of food can quickly lead to weight gain, mostly in the form of fat. Remember, during the restrictive period, our body broke down muscle for protein, which slowed down our metabolism, so as soon as we “break” our diet and start reincorporating foods, our body stores the food as fat to prepare for any future states of famine or extreme restriction. If we reintroduce carbs, we will also gain back all that water weight as the body replaces our glycogen stores.
Now, we not only weigh what we did before we went on the diet, but our body composition has changed. We have more fat and less muscle than the last time we were at this weight, which means our metabolism is slower, making it even more difficult to lose weight the next time around. And so the cycle of yo-yo dieting continues…
This is upsetting and we hear you!
We have seen the frustrations that come along with yo-yo dieting. It’s exhausting to put in all the hard work only to end up back where you began! It not only takes a physical toll on the body, but also a psychological toll on the mind. You may think there is something wrong with you, when really the diet is to blame.
That is why at 4Q Method we are committed to stopping this vicious cycle once and for all! We show our clients that weight loss does not need to be difficult or complicated and help them achieve the lasting weight loss they are looking for.