Effect: What is it and Why does it Happen? 【HSN Blog】


Yo-yo Effect: Why does it happen?Yo-yo Effect: Why does it happen?

Today, we are going to explain what is the yo-yo effect and why does it happen.

Losing weight is not an easy task. In fact, millions of people wake up every day thinking about trying a new diet or which gym should they go to in order to lose that extra weight. But you know what?

Losing weight is relatively easy. Yes, I am not joking.

Actually, it is not that difficult to follow an acute calorie restriction using different factors. That is precisely where many books, Youtube channels or companies earn their money from. People will lose weight with just a little help.

What is the big issue then? It actually comes afterwards and we barely even notice it. In fact, we start gaining weight once again, this phase is popularly known as the yo-yo effect.

What is the yo-yo effect?

Wing and Hill stated in 2001 that succeeding in losing weight is a voluntary loss of at least a 10% of the starting weight. Then, we have to be able to maintain said weight for a year or more (1).

According to this statement, we could define the yo-yo effect as:

Not being able to maintain our weight after losing some of it. Consequently, we end up having either the same weight as we did at the beginning and sometimes even more.

Yo-yo effect

In other words, losing weight to gain it once again, sometimes even more.

What are the causes of the yo-yo effect?

There are many, some of them can be prevented, but others not so much.

Let’s see some of the most important ones.

Loss of muscle mass and associated metabolic changes (2)

There is something inherent to weight loss which is the total of lost kilos, a part of it is fat-free mass.

What is this? It is mainly muscle and bones.

If we want to quantify this loss approximately, a forth of the lost weight is fat-free mass.

But, what are the consequences of this? That your body spends energy.

What we spend in a day is known as the total daily energy expenditure or TDEE.

There are different tissues that contribute to this total daily energy expenditure, the muscle being one of those that use more energy.

Apart from this, more muscle means more functionality and more physical activity in general. That is why, you will realize that it is crucial to protect the muscle mass during fat loss processes.

Then, what can we do? Well, mainly two things:

  1. Increasing the protein intake during the weight loss period. The higher the calorie deficit, the higher the protein intake will be.
  2. Doing strength training, which is crucial if we want to avoid losing muscle tissue.

Hormone physiological changes that regulate the hunger-satiety processes

The body regulates these processes with signals from the arcuate nucleus, parts of the brain cortex and the limbic system.

Sometimes, physiology is perverse and it makes it difficult for us to lose weight. Why?

There are peptides known as anorectic, which are those that calm the appetite. Also, there are others known as orexigenic, which are those that increase the appetite.

  • Hypothalamus: for example, we have the neuropeptide Y, the Agouti protein (orexigenic) and Pro-opiomelanocortin and CART (anorectic).
  • Digestive system: we have GIP, ghrelin (orexigenic) and the GLP-1, YY peptide or cholecystokinin (anorectic).
  • Pancreas: where we can find the pancreatic polypeptide and amylin.
  • Leptin in the adipocytes.
  • And finally, in the CNS, we have dopaminergic, opioidergic and cannabinoid mechanisms that regulate the reward system.

Hormone system

Complex, right? Well, if you want to find out how these hormones work, click here

In reality, the toughest part is that most of the levels of these anorectic hormones drop, while the orexigenic ones increase, like this study shows (2).

The nutritional approach

This is a controverted issue.

On the one hand, there is no solid evidence that a low carb diet is going to help us maintain our weight in the long term. However, there are some studies that show just the opposite.

Among the subjects from this study by JAMA (3), most of them lost between a 10 and 15% of their body weight. This happened after following a diet that was either low in fat or low in carbs for 4 weeks.

What is interesting is that the Total Energy Expenditure and the Energy Expenditure while Resting dropped more in the low-fat group than in the low-carb group. At first, this diet would provide more advantages in terms of preventing the yo-yo effect.

Nut butter

However, as we said before, this topic is not clear at all.

Going back to previous habits

Apart from the biological and physiological factors that we have previously described, there are also behavioral and environmental factors that are even more important.

Repeat with me: if we do not change our habits, we will not succeed in losing weight.

If you do not follow the following tips, it will not matter if you do a miracle diet based on meal replacements, or a successful intermittent fasting, or lose 20 kilos after going to the gym. All in all, everything you have done will be in vain. Make sure to…

  • Learn what are the healthiest and most satiating products
  • Know what to do when you feel hungry or cravings
  • Exercise even if you do not feel like it
  • Differentiate between emotional hunger and real hunger

According to all this information, it is easy to understand that we need to start following healthy habits from an early age. Read more….

Other factors (4)

If chronic stress or sleep deprivation made you gain weight in the first place, what makes you think it will not happen again after losing weight?

In fact, it will happen due to the physiological factors that we mentioned before. That is why many people do not only gain the weight they lost, but they even weigh more than when they started.

Physical exercise

That is the cruelty of physiology.


Finally, I would like to say changing your environment and habits is one of the most effective ways to avoid gaining weight once again.

If you lived in an obesogenic environment where:

  • Your family ate processed products on a daily basis.
  • You did not do any physical exercise at all.
  • You experienced a lot of stress in that environment (it could be family, friends, work…).

Obesogenic environment

The only thing you can do is running away from that toxic environment.

In the end, the environment is probably the most determining factor, since we live in a society where more than a 50% of the population is overweight or suffers obesity.

That is all for today. Perhaps you still want to know more about what you can do to avoid the yo-yo effect. There will be more details in the next article with very useful strategies. Here’s a clue: energy flow

See you in the next one!


  1. Wing RR, Hill JO. Successful weight loss maintenance. Annu Rev Nutr. 2001.
  2. MacLean PS, Bergouignan A, Cornier MA, Jackman MR. Biology’s response to dieting: The impetus for weight regain. American Journal of Physiology – Regulatory Integrative and Comparative Physiology. 2011.
  3. Ebbeling CB, Swain JF, Feldman H a, Wong WW, Hachey DL, Garcia-Lago E, et al. Effects of dietary composition on energy expenditure during weight-loss maintenance. JAMA [Internet]. 2012;307(24):2627–34.
  4. Greenway FL. Physiological adaptations to weight loss and factors favouring weight regain. International Journal of Obesity. 2015.

Related Entries

  • Living in an obesogenic environment can condition our lifestyle, keep reading…
  • Can you burn the same fat if you follow a diet high in fat or carbohydrates? If you want to know the answer, make sure to click here

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