Protein Burns More Calories Than Carbs. Here’s Why That Matters.

You eat a meal, your body digests it, absorbs the nutrients and then puts those nutrients to work. But here’s something most people don’t realize: your body actually has to spend energy to process the food you eat.

That process is called the thermic effect of food, or TEF. Think of it as the small energy bill your body pays to digest, absorb and process your meal.

And not all calories cost the same to process.

Protein has the highest thermic effect of the three macronutrients. Research has generally found that your body uses roughly 20 to 30% of the calories from protein during the processing of that protein. Carbohydrate is around 5 to 10%, while fat is much lower, generally around 0 to 3%.

So, if you eat 100 calories from protein, roughly 20 to 30 calories may be used in the process of handling those calories. With 100 calories of carbohydrate, it might be closer to 5 to 10 calories. With fat, only about 0 to 3 calories.

Now, before you start looking at your chicken breast like it is a miniature furnace, there is an important reality check.

This does not mean protein gives you “free calories.”

The thermic effect is only one small piece of your overall daily energy expenditure. It also does not mean that simply adding protein to your diet automatically causes fat loss.

However, when protein replaces some carbohydrate or fat while total calories remain similar, that higher thermic effect can increase the amount of energy your body uses to process the food. A 2024 systematic review and meta-analysis of 52 studies found that higher-protein meals increased diet-induced thermogenesis compared with lower-protein meals. Longer-term studies also found modest increases in total daily energy expenditure with higher protein intake.

That is useful.

But protein has another potential advantage that may be even more practical: appetite.

Protein appears capable of influencing several of the signals involved in hunger and fullness. Research has found that higher-protein meals can increase GLP-1, a hormone involved in appetite regulation and slowing digestion, while some studies have also found reductions in ghrelin, one of the hormones involved in stimulating hunger. A systematic review and meta-analysis of randomized controlled trials found that protein intake generally reduced hunger and increased fullness in short-term studies, while also increasing GLP-1 and decreasing ghrelin.

But here is where things get interesting.

Higher protein does not automatically mean you will eat less.

In one randomized crossover trial, a high-protein meal increased GLP-1 and PYY, two hormones associated with satiety, but participants did not consume significantly fewer calories at the following meal. Another randomized trial found that increasing protein from 10% to 30% of calories produced only a modest improvement in daily fullness, with no significant differences in hunger or desire to eat.

In other words, the food itself still matters.

A grilled chicken breast, Greek yogurt, eggs or lean beef may be pretty satisfying for the calories they provide. But a highly processed “high-protein” snack that comes with plenty of calories may not magically shut down your appetite.

This is why I like to think about protein as one tool in the toolbox rather than a nutritional superhero.

Getting enough protein can help you preserve and build muscle, it requires more energy to digest than carbohydrate or fat, and it may improve fullness and appetite regulation for some people. Those benefits can be particularly useful when you're trying to lose body fat while maintaining the muscle and strength you worked hard to build.

The bigger picture is still calories, food quality, adequate protein, resistance training, movement and consistency.

So yes, protein burns more calories during digestion than carbs or fat.

Just don't expect your chicken breast to pay your entire calorie bill.

What This Means For You

Instead of obsessing over whether every meal is “perfect,” start by asking a simpler question:

“Where is my protein?”

Build your meals around a quality protein source, add minimally processed carbohydrates, include healthy fats and plenty of fruits or vegetables, then adjust portions based on your goals.

That is a much more useful strategy than chasing the latest metabolic hack.

Want Help Putting This Into Practice?

If you're struggling to figure out how much protein you actually need, how to build balanced meals or how to make your nutrition work with your training and real life, let's talk.

15-Minute Nutrition Strategy Call

Because nutrition should help you perform better, feel better and stay strong for the life you're living, not make you spend your day calculating whether your lunch burned three extra calories.

References

• Acheson KJ. Thermic effect of food and sympathetic nervous system activity in humans. PubMed.

• Guarneiri LL, et al. Effects of Varying Protein Amounts and Types on Diet-Induced Thermogenesis: A Systematic Review and Meta-Analysis. 2024.

• Kohanmoo A, et al. Effect of short- and long-term protein consumption on appetite and appetite-regulating gastrointestinal hormones: A systematic review and meta-analysis of randomized controlled trials. 2020.

• Bowen J, et al. High protein intake stimulates postprandial GLP-1 and PYY release.

• Pesta DH, et al. A high-protein total diet replacement increases energy expenditure and leads to negative fat balance in healthy, normal-weight adults.