4 Common Causes of Weight Gain after a Diet

We must keep in mind that the key to losing weight is not in going on a diet, but in adopting healthy eating habits and sticking to them.
4 Common Causes of Weight Gain after a Diet
Valeria Sabater

Written and verified by psychologist Valeria Sabater.

Last update: 27 May, 2022

Has this happened to you before? You go on a rigorous diet for three months, to prepare for the summertime or perhaps just to have a better figure by losing a few pounds. And you succeed! You’ve finally achieved your ideal weight. However, after a few weeks, you find yourself gaining the weight back quickly.

Why does this happen so often to us? Have we done something wrong? We want to explain in this article some of the most common causes of unexpected weight gain.

Why are you gaining back the weight?

Next, we’ll share four of the main reasons why you gain the weight back after weight loss. Take note and avoid these common mistakes.

1. Skipping meals

Woman biting her nails and skipping a meal

Here’s a simple example to understand why: imagine your friend wants to lose weight quickly for the summer. To do so, she begins her own regimen, which is nothing more than skipping dinner, eating very little for breakfast, and in the middle of the day snacking on everything she sees, so doesn’t eat anything when she gets home.

And suppose that each day, 10 to 12 hours go by without eating anything. This actually puts the body into an “alert state” and it looks for energy reserves, wherever they may be found. However, when it returns to normal the opposite occurs.

Your body will quickly recover the energy reserve that was lost in order to cover this unexpected lack and in order to prevent new situations from putting our body into an alarm mode.

That is to say, what our friend has achieved is not healthy. We cannot stop eating for a day nor limit ourselves to two meals a day. Our body processes this as a threat and as a consequence, our brain reacts by storing fat in case of future periods of fasting.

2. The dangers of low-calorie diets

We have a classic example of those very restrictive diets where you eat five meals but they are nutritionally imbalanced and can be dangerous for your body.

Especially dangerous are those diets that want you to consume less than 1,200 calories per day, or those which recommend consuming almost exclusively carbohydrates or only protein.

This is something very dangerous for our health. Normally these diets are followed for a short period of time, two or three weeks. Several studies have found that after achieving the desired weight, people often gain it back. It happens once you return to eating some type of caloric food, even if just a little bit.

Take note as to why this happens:

These types of restrictive diets lower the body’s level of glycogen, so the body tends to search for this element in other places. And do you know where it is found? In our muscles, in our cartilage… It is in these areas where a certain amount of energy can be obtained, and by doing so, it releases a great quantity of water along with minerals and toxic substances resulting from their metabolism. For example, this occurs with our urea and uric acid.

When the supposed “miracle diet” ends, you have lost weight due to the consumption of glycogen stored in the liver. This is done by having gone to the muscles and ligaments in search of energy and by having lost water and minerals essential to the body.
This deficit makes the tissues look for ways to “rehydrate” again and quickly. Even more so once you return to a normal diet, by storing up fat and calories. Thus the lost pounds return in just a short time.

3. The need to incorporate healthy habits in our diet

Woman eating a salad trying to eat healthily

If a certain diet has helped you feel better, why stop it? Many times we tend to gain weight because we maintain some dietary habits that are not only wrong but also unhealthy.

You already know that the consumption of fats, sweets or processed foods, can raise cholesterol levels, hypertension and other illnesses which are very dangerous for our heart.

Therefore, to avoid weight gain, you should incorporate a diet that has helped you before into your eating habits. However, this does not mean that you cannot allow yourself to eat some sweets. Just as long as you know that you will go for a walk later and can thereby burn calories.

Generally, when trying to lose weight, it is always best to consult with a nutritionist. Sometimes, it could be that some foods make us feel ill, or that some combinations of foods are not good for us. The first thing is to know how to listen to and understand your body. When you come up with something that works well, you should always include it in your daily diet.

4. Changes in your routine

Many people on a subway possibly going to work

This happens often. One of the most frequent causes of weight gain is a change in habits. Or even something happens in your life that makes you gain weight again. Do you want some examples? It’s likely you know about some of these situations:

  • You have just lost a few pounds, but in your work, there is a change of routine. This means that your life habits also change. After a short time, you gain back the weight you lost.
  • Problems you may be having with your partner
  • You’re feeling more anxiety for problems at home, at work…
  • You have lost weight for the summer but, sometimes the vacation season makes us relax. We may go out more to bars, to parties… And as a consequence, we experience a weight gain.

In conclusion

Diets aren’t something that you should do every once in a while. Instead, a healthy diet should be part of your every day, along with other healthy habits. That way, you’ll lose weight, and you’ll keep it off. As always, if you have any questions or concerns, talk to your doctor or a nutritionist. You can also learn more by checking out the information in our bibliography for today’s article.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Nardone, Giorgio. La dieta de la paradoja: Superar las barreras psicológicas que te impiden adelgazar y estar en forma. Vol. 72. Grupo Planeta (GBS), 2009.
  • Pérez-Lizaur, Ana Bertha. Dietas normales y terapéuticas: los alimentos en la salud y la enfermedad. McGraw Hill Mexico, 2014.
  • Tajer, Carlos D. “La obesidad y sus paradojas: tratando de elaborar un mensaje coherente para la prevención secundaria.” Revista argentina de cardiología 80.2 (2012): 195-204.
  • Dulloo, A. G., Jacquet, J. and Montani, J. P. (2012). How dieting makes some fatter: from a perspective of human body composition autoregulation. The Proceedings of teh Nutrition Society, 71(3), 379-389. https://doi.org/10.1017/S0029665112000225
  • Weyer, C., Walford, R. L., Harper I. T., Milner, M., MacCallum, T., Tataranni, P. A. and Ravussin, E. (2000). Energy metabolism after 2 y of energy restriction: the biosphere 2 experiment. The American Journal of Clinical Nutrition, 72(4), 946-53. https://doi.org/10.1017/S0029665112000225
  • Trexler, E. T., Smith-Ryan, A. E. and Norton, L. E. (2014). Metabolic adaptation to weight loss: implications for the athlete. Journal of the International Society of Sports Nutrition, 11(7). https://doi.org/10.1186/1550-2783-11-7

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.