Eating too much protein can turn into fat and increase your weight, but it’s not as easy on your body as turning carbs or fat into fat tissue.
Can protein make you fat?
The body turns excess glucose into fat if you don’t need it for energy. The fact is that protein is not usually converted into glucose; your body “prefers” carbohydrates and fats for these purposes because they are the easiest to convert into calories.
Do you need protein for energy?
Protein, of course, carries energy in the form of 4 kcal. But the body uses protein as energy last. First of all, protein is a building material for cells; enzymes are formed from it, which control many processes in our body.
How does protein intake affect body weight?
Many studies note that even with severe overeating of protein, adipose tissue remains virtually unchanged.
A 2016 study published in the Journal of Nutrition and Metabolism found that when healthy, trained men consumed 3.3 grams of protein per kilogram of body weight per day (g/kg/day) for four months, they did not gain fat compared to those who followed a traditional healthy diet. (However, they did not have any changes in blood lipids or liver and kidney function).
Another widely cited study in the Journal of the International Society of Sports Nutrition found that when healthy, trained men increased their protein intake to 4.4 g/kg/day—five and a half times the recommended daily value—their body fat did not increase at all over the course of two months.
But what if you’re someone who doesn’t exercise much and you’re overeating on protein?
Where does excess protein in the body go?
Protein is first broken down into amino acids in the stomach and intestines. They are transported through the bloodstream to the liver and other organs and tissues, where they are used as functional units.
But the body cannot store amino acids. So if you eat more than you need to create functional proteins, they will be converted into glucose
in the form of glycogen or, as a last resort, for energy.
Glucose can also be converted to triglycerides and stored as fat. Some amino acids are ketogenic (such as leucine and lysine) and are preferentially converted into ketones, an alternative source of energy.
Thus, amino acids from excess dietary protein can be converted into:
- Urea, which is excreted in urine.
- Glucose, which is used for energy and stored as glycogen.
- Fat (excess glucose is converted to triglycerides and stored as fat).
- Ketones (alternative energy source) from ketogenic amino acids.
- Energy obtained directly from amino acids.
However, using protein for energy isn’t the easiest, so the body only uses it as a last resort when there aren’t enough carbohydrates or fats (or you’re eating much more protein than you need in amino acids).
Fat accumulation from protein
Theoretically possible, but unlikely. Increasing your protein intake is generally associated with higher satiety, weight loss, and fat loss over time. But of course, this depends on what you eat and the type and amount of physical activity. Additionally, many high protein foods contain more than just protein.
Eating a lot of protein can also mean you’re likely to eat more fat and carbohydrates, especially if you love cheese or meat. However, eating more protein usually results in eating fewer calories because protein has a higher satiety index than fats or carbohydrates.
Many people find it difficult to eat large amounts of protein, but if you want to snack on something, choose protein options. They are highly likely to not affect your waistline.