Can collagen supplements make you fat? Read about calories and weight gain

Collagen supplements have become a wellness staple, praised for their ability to improve skin, strengthen hair, and support joint health. You’ll find them in powders, pills, and even added to coffee creamers and snack bars. But as with any popular supplement, questions and myths arise. One common concern is whether adding collagen to your daily routine could lead to unwanted weight gain.

This article will explore the relationship between collagen, metabolism, and body weight. We'll look at the science, consult expert opinions, and analyse what's really inside your supplement tub. By the end, you'll have a clear, evidence-based answer to the question: can collagen make you fat?

What exactly is collagen and does it contain fat?

Before we can understand its effect on weight, it’s important to know what collagen is. Collagen is the most abundant protein in the human body, making up about 30% of our total protein content. It’s a vital structural component of skin, bones, muscles, tendons, and other connective tissues. Think of it as the "glue" that holds your body together.

Our bodies naturally produce collagen, but production starts to decline in our mid-to-late twenties. This decrease contributes to common signs of ageing, like wrinkles and joint pain.

Collagen supplements are typically derived from animal sources—like bovine (cow) hide or marine (fish) scales—and are hydrolysed (see our bovine collagen powder; and marine collagen powder). This means the large protein molecules are broken down into smaller peptides. Pure collagen is essentially a protein isolate; it does not contain fats or carbohydrates, which are often the culprits behind hidden calorie spikes.

A look at collagen calories and potential fat storage

When considering weight gain, calories are a crucial part of the conversation. Any food or supplement containing calories has the potential to contribute to weight gain if it pushes your total daily energy intake above what your body burns.

Collagen is a protein, and like all proteins, it contains calories. On average, one gram of protein provides about 4 calories. A standard serving of a collagen peptide supplement is usually between 10 to 20 grams, which translates to approximately 40 to 80 calories.

For most people, adding 40–80 calories to their daily diet is unlikely to cause significant weight gain, especially if they lead an active lifestyle or are mindful of their overall calorie intake. You could easily burn these calories with a brisk 10-minute walk. The key is to be aware that collagen supplements are not calorie-free and should be factored into your daily energy budget, but they do not inherently "create fat."

Why collagen might increase weight without making you fat

Another piece of the puzzle is collagen's effect on muscle. While it isn't a complete protein (it lacks the essential amino acid tryptophan), it is rich in other amino acids like glycine, proline, and arginine, which are important for muscle tissue.

So, how does this relate to weight? Muscle tissue is denser and weighs more than fat tissue. If collagen helps you build muscle, you might see the number on the scale go up. However, this is a positive form of weight gain that reflects an increase in lean body mass, not fat. Muscle tissue is metabolically active, meaning the more you have, the more calories your body burns at rest.

Several studies have shown promising results. A 2015 study published in the British Journal of Nutrition found that elderly men who combined resistance training with collagen supplements saw a greater increase in muscle mass and strength compared to those who only practiced resistance training. This suggests that while your weight might change, your body composition is actually improving.

Hidden ingredients that could lead to weight gain

If you find yourself gaining fat while taking collagen supplements, the collagen itself may not be to blame, but rather the "extras." Many collagen powders are flavoured or part of pre-mixed "beauty tonics" that contain added sugars, thickeners, or artificial sweeteners that can cause bloating or weight gain.

To ensure your supplement doesn't make you fat, look for "unflavoured" versions with 100% collagen peptides and zero added sugars or fillers.

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