Why Do Some People Gain Weight Faster than Others?

While there are certain fixed factors that make some people put on weight faster than others, other factors can be changed to help lose weight.
Why Do Some People Gain Weight Faster than Others?
Eliana Delgado Villanueva

Reviewed and approved by the nutritionist Eliana Delgado Villanueva.

Written by Lorena González

Last update: 26 May, 2022

You’ve probably noticed how some people eat tons and don’t gain any weight, meanwhile other people gain weight much faster even by eating regular amounts of food. Today, we want to explain a bit about this common phenomenon.

Why some people gain weight faster than others

1. Genetics

person eating popcorn and sandwich on couch

Genetics is one of the main factors in a lot of things related to the body, because it  determines several crucial aspects of our lives.

So, it also plays a role in why some people gain weight faster than others, who seem like they can eat forever and not put on a pound.

  • This is now a proven fact. Because human genome experts have managed to separate out the genes that are responsible for the distribution and accumulation of fat.
  • The FTO gene (associated with fat mass and obesity) is found in 82% of men, meaning that they have a greater tendency to put on weight no matter how little they eat.

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2. Diet

Genetics is a fundamental part of this puzzle, but so is diet. It’s one of the keys  determining why you lose or gain weight faster or slower than others.

It’s also worth pointing out that some of the genes related to gaining weight cause a natural craving unhealthy foods.

This is why it’s important to be disciplined and pick up healthy habits that can help you reject the effects of this gene.

Bear in mind that once you start to follow a healthier and fresher diet, you’ll probably feel much better.

Once you start, your own body will even ask you to keep eating healthily once it gets used to it. Give it a try!

3. Exercise


Of course, the amount of exercise you do is another key factor when it comes to maintaining a healthy weight.

Oftentimes, what sets apart the people who are gaining weight much faster from the people who aren’t is the amount of physical exercise they do.

But you should bear in mind that doing certain kinds of exercise alone might not help you lose weight, though they can control how much you gain.

You should also keep in mind that everyone has different individual needs, and that also applies to the amount of exercise people need to do .

Some people need to do two hours of cycling to burn 200 calories, meanwhile thirty minutes is enough to consume the same amount for others.

Don’t reward yourself with food for having done a specific amount of exercise, because that does no good for your health, either.

For example, it’s not good to eat more than usual as compensation for having done enough exercise.

The only thing you’ll achieve by doing this is making all your exercise in vain. Plus, it can even end up cause you to gain weight.

4. Stress and lack of sleep

Both stress and lack of sleep can be an obstacle to staying in shape. These two factors can have a direct impact on your weight and make you pack on the pounds.

When under the effects of stress, we often choose unhealthy foods because we like them more and they make us feel better.

But that’s exactly what you should be avoiding so that you don’t adopt unhealthy lifestyle habits.

5. Loss of intestinal biodiversity

According to various studies, alterations in the intestinal flora are associated with health issues like obesity and type 2 diabetes.

The composition and diversity of intestinal flora are linked to weight gain, not only because of you’ve lost some gut bacteria, but also because not as much is being produced.

This can happen as a result of an inappropriate diet or excessive use of antibiotics. But why does it lead to weight gain?

Changes in the intestinal flora can cause people to generate up to 150 calories more each day, even if they eat the exact same amount as someone else. All those extra calories can definitely lead to long-term weight gain.

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.

  • Doo M., Kim Y., Obesity: interactions of genome and nutrients intake. Prev Nutr Food Sci, 2015. 20 (1): 1-7.
  • Rynders CA., Thomas EA., Zaman A., Pan Z., et al., Effectiveness of intermittent fasting and time restricted feeding compared to continuous energy restriction for weight loss. Nutrients, 2019.
  • Rajan TM., Menon V., Psychiatric disorders and obesity: a review off association studies. J Postrgrad Med, 2017. 63 (3): 182-190.

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