Do we all gain the same amount of fat from the same calorie surplus?

Posted by Dayne Hudson in Weight Loss

Estimated reading time: 4mins

Do we all gain the same amount of fat from the same calorie surplus?

Genetics and our ability to gain fat

You've probably noticed that some people tend to gain more weight than others.

Some people can get better weight loss results from dieting in a short amount of time, whilst others have to work really hard. There are many factors at play here, namely, genetics.

Your genetics play a role in energy balance and nutrient partitioning which govern fat loss.

To illustrate how this works, consider this study which overfed 12 twins by 1000 calories for 84 days, with each twin entering a surplus of 84,000 calories over the period!

And what did they find?

The average weight gained was 8.1 kilograms, but there was a huge difference in the range: 4.3 kilograms to 13.3 kilograms!

The authors concluded that "genetic factors" are involved, which may govern the tendency to store energy as either fat or lean tissue.

The researchers added that these genetics accounts for around 40% of the variation in weight gain and fat distribution!

Do you have a brother or sister that seems like they always add more or less weight than you? Well, now you know why!

Genetics play a large role in how much weight you gain.
Genetics play a large role in how much weight you gain.

Further research has discovered that our body fat distribution is approximately 22-61% explained by the genetics we've inherited.

Now sure, genes affect energy balance, but the fundamental fact remains: weight loss can only occur in a calorie deficit.

And this phenomenon has been seen in other studies, too.

How NEAT helps us fight weight gain

NEAT stands for non-exercise activity thermogenesis. It refers to our daily movements that burn calories that aren't specifically exercise. For example:

  • Walking to the bathroom
  • Grocery shopping
  • Cleaning your living space
  • Playing with your kids
  • Gardening
  • Walking your dog
  • Walking to your next meeting
  • Taking the stairs when you can
  • Stand instead of sit
  • Maintaining posture
  • Tapping
  • Chewing gum

These activities might not seem like "hardcore exercise."

But consider research suggests we can burn an extra 350 calories a day from NEAT activities!

NEAT plays a large role in how we burn excess calories.
NEAT plays a large role in how we burn excess calories.

And this brings us to the point: Some of us have a higher level of NEAT, and thus burn more excess calories than others. 

For example, in this study, 16 subjects (4 females and 12 males) were overfed 1000 calories for 8 weeks.

Over the 8 weeks, an average of 432 calories per day was stored, and 531 were burned during increased energy expenditure. And the difference in fat gained was huge: 0.36kg to 4.23kgs!

And this was due to NEAT.

This may be you or it may not, but some people can burn an astronomical amount of calories even after being overfed, via NEAT, in response to overfeeding.

They tap their feet, bounce their leg, whatever it is.

In fact, one subject's NEAT increased so much that they torched 700 of the 1000 calorie surplus!

In another study, resistance-trained subjects were overfed 800 calories per day from NEAT. But this was different: it was via whey protein.

And because of protein's high thermogenic effect (30%), the subjects gained NO body fat!

Bulk Nutrients WPC
Bulk Nutrients WPC

A lean protein source like Bulk Nutrients WPC is great for when you want to consume more calories than you burn, for limited fat gains!

So if you're someone who you feel gains fat relatively easily in a surplus, then ensure your overfeeding comes from lean protein sources, in which case you're less likely to gain a lot of fat.

The bottom line on a large calorie surplus

Is that a large calorie surplus means we'll gain weight, but how much we gain is dependent on factors like genetics, and NEAT, which stands for non-exercise activity thermogenesis. In one study, where the weight gained was 8.1 kilograms after subjects were overfed, the difference in fat gained was between 4.3 kilograms to 13.3 kilograms! If you're really hungry and want to eat more calories than you burn, consider getting them from protein. Otherwise, try and get into the habit of increasing your NEAT. Generally, two people gain a different amount of weight from the same calorie surplus.


  1. Bouchard C, Tremblay A, Després JP, Nadeau A, Lupien PJ, Thériault G, Dussault J, Moorjani S, Pinault S, Fournier G. The response to long-term overfeeding in identical twins. N Engl J Med. 1990 May 24;322(21):1477-82. doi: 10.1056/NEJM199005243222101. PMID: 2336074.
  2. Schleinitz D, Böttcher Y, Blüher M, Kovacs P. The genetics of fat distribution. Diabetologia. 2014 Jul;57(7):1276-86. doi: 10.1007/s00125-014-3214-z. Epub 2014 Mar 16. PMID: 24632736.
  3. Strasser B, Spreitzer A, Haber P. Fat loss depends on energy deficit only, independently of the method for weight loss. Ann NutrMetab. 2007;51(5):428-32. doi: 10.1159/000111162. Epub 2007 Nov 20. PMID: 18025815.
  4. Chung N, Park MY, Kim J, Park HY, Hwang H, Lee CH, Han JS, So J, Park J, Lim K. Non-exercise activity thermogenesis (NEAT): a component of total daily energy expenditure. J Exerc Nutrition Biochem. 2018 Jun 30;22(2):23-30. doi: 10.20463/jenb.2018.0013. PMID: 30149423; PMCID: PMC6058072.
  5. Levine JA, Eberhardt NL, Jensen MD. Role of nonexercise activity thermogenesis in resistance to fat gain in humans. Science. 1999 Jan 8;283(5399):212-4. doi: 10.1126/science.283.5399.212. PMID: 9880251.
  6. Leaf A, Antonio J. The Effects of Overfeeding on Body Composition: The Role of Macronutrient Composition - A Narrative Review. Int J Exerc Sci. 2017;10(8):1275-1296. Published 2017 Dec 1.
  7. Pesta DH, Samuel VT. A high-protein diet for reducing body fat: mechanisms and possible caveats. NutrMetab (Lond). 2014;11(1):53. Published 2014 Nov 19. doi:10.1186/1743-7075-11-53

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