Can Eating Protein Make You Fat? 5 Reasons Why Not

You’ve probably seen the following phrase parrotted around the internet:

If you eat more calories than you burn, you will gain weight

If you burn more calories than you eat, you will lose weight

Simple math. The laws of thermodynamics in action. Makes sense, right?

While this is largely true as it relates to fats and carbohydrates, when it comes to protein, it’s not that simple.

For example, one study done on sedentary individuals eating the same amount of calories on various diets found that those on a high-protein diet gained less overall weight, increased their fat-free body mass, and gained dramatically less body fat.

In resistance trained individuals, the importance of protein becomes even more apparent. One study examined 17 resistance-trained female subjects that were matched for total fat mass and randomized to a high-protein (2.4 g/kg/d) or control group (1.2 g/kg/d) for eight weeks in conjunction with a resistance-training program. The high-protein group consumed significantly more calories (+400 kcal) and protein than the control group. The higher protein diet was shown to be superior to a lower protein diet for increasing fat-free mass, but both diets similarly reduced fat mass. This suggests excess protein may even result in fat loss while in a caloric surplus.

So what’s happening to the excess protein calories that isn’t happening with excess carbohydrates or fat? Why doesn’t eating excess protein necessarily make you fat?

There are a few reasons protein is special:

  1. Protein’s thermic effect of food (TEF)
  2. Non-Exercise Activity Thermogenesis (NEAT)
  3. Protein does not convert efficiently to fat
  4. Increased absorption from resistance training
  5. Higher Satiety

Thermic Effect of Food

After we eat, there is an increase in energy expenditure at each stage of food processing, including: digestion, absorption, transport, metabolism, and storage. This is called the Thermic Effect of Food (TEF), or Dietary Induced Thermogenesis (DIT).

We don’t store away all the excess energy we consume - some of it is burned in the digestion process itself. This is especially true for protein.

Reported TEF values for the 3 macronutrients are :

  • 0-3% for fat
  • 5-10% for carbohydrates
  • 20-30% for protein 

A researcher named Livsey concluded that every gram of protein, normally 4 calories, should be more accurately listed as 3.2 calories per gram. This would mean that for every calorie of protein you consume, 25% of the energy is used up simply in digestion. 

The excess calories we eat from protein simply aren’t digested as efficiently as carbs or fats, resulting in less stored body fat.

Non-Exercise Activity Thermogenesis (NEAT)

When we eat excess calories, our bodies will attempt to burn them off through spontaneous physical activity, called Non-Exercise Activity Thermogenesis (NEAT).

Have you ever unconsciously and uncontrollably drummed on your desk, or bounced your leg under your desk? That’s NEAT in action. This extra motion can burn an extra 350 calories per day, and protein drives more NEAT than the other macronutrients.

It’s not totally understood why excess protein increases NEAT, but it may have to with proteins' effect on neuropeptide concentrations. 

Nonetheless, the increased activity burns off more calories, as compared to fats and carbs - and that’s less calories turned into fat.

Gluconeogenesis & Lipogenesis

The calories in vs calories out (CICO) argument for gaining and losing weight would lead us to believe that any calories not used in our bodies throughout the day is eventually stored as fat. 

For protein to convert into fat, it must first be converted to carbohydrates (glucose) via a process called gluconeogenesis, then the carbs are converted to fat if not needed for energy.

However, it does not appear that a simple conversion of 1 excess protein calorie will be converted to 1 calorie of carbs or fat.

In one experiment, it was found that even under optimal conditions, only 8% of protein consumed was eventually converted to glucose

It’s simply not an efficient way for your body to obtain glucose. There are also other uses for the excess protein that your body prefers - it can be stored in muscle tissue and organs, or used to support enzymes and immune cells. The body also has the ability to excrete excess proteins via the urea cycle

Furthermore, recent animal data suggest that a high-protein diet might REDUCE fat mass by inhibiting lipogenesis.

So while a small amount of excess protein may be eventually stored as fat, it’s much less likely than carbs or fat.

Resistance training

As seen in one of the studies I cited at the beginning, resistance training throws another wrench in the theory that “excess protein is turned into fat”.

It is well known that if you want to gain muscle, you must consume adequate protein to stimulate protein synthesis.

In another study, 48 healthy, resistance-trained men and women to consume a minimum of 3 g/kg of protein daily or to maintain current dietary habits for eight weeks while undergoing a standardized resistance training program designed to increase lean body mass. Compared to the control group, the high-protein group consumed significantly more calories (+ 490 kcal) and protein (3.4 vs. 2.3 g/kg) from primarily whey protein shakes, leading to a diet that was 39% protein, 27% fat, and 34% carbohydrate. Both groups significantly increased fat free mass and significantly reduced body fat compared to baseline, but the reduction in fat mass was significantly greater in the high-protein group compared to the control group (−1.6 vs. −0.3 kg). 

So, when combined with resistance training, eating excess protein calories on top of your existing diet not only increases muscle mass, but can simultaneously reduce body fat. 

This flies in the face of the theory that excess protein = body fat.

Increased Satiety

Lastly, due to the high satiating effect of protein, it’s simply very hard to overeat protein.

Studies show that protein is by far the most filling. It helps you feel more full — with less food.

This is partly because protein reduces your level of the hunger hormone ghrelin. It also boosts the levels of peptide YY, a hormone that makes you feel full

These effects on appetite can be powerful. In one study, increasing protein intake from 15% to 30% of calories made overweight women eat 441 fewer calories each day without intentionally restricting anything

Think about how easy it is to fill up on steak as compared to a bag of chips.

Milk proteins, such as high-protein cheese, seem to have a greater effect on satiety than other types of proteins.

Even if we did easily gain fat from excess protein, it would be much harder to compared to high-carb or fatty foods because of how filling it is.


While it’s possible excess protein can result in fat, Dietary protein appears to have a protective effect against fat gain during times of energy surplus, especially when combined with resistance training. Therefore, the evidence suggests that dietary protein may be the key macronutrient in terms of promoting positive changes in body composition.

Take advantage of the benefits protein has to offer, order some Proteina High-Protein Cheese today.


While it can be hard to do, there is such a thing as too much protein. Too much protein can lead to a high acid load on your kidneys. Keeping protein below 3g per kg of body weight will minimize that risk.