When you eat food, your body has to break it down into smaller, usable forms that can be moved around the body. Proteins are broken down into amino acids.

Digestion begins in the mouth as you chew food into smaller pieces. From there, digestive enzymes in your saliva start to break down carbohydrates and fats. Protein digestion begins in the stomach, where pepsin is secreted to break down protein into smaller peptides. 

“The stomach produces hydrochloric acid (HCl) and pepsinogen, an inactive form of the enzyme pepsin. The acidic environment of the stomach activates pepsinogen to pepsin, which starts breaking down proteins into smaller peptides (short chains of amino acids),” explains Ashley Sauvé, CHN, a certified holistic nutritionist and herbalist specializing in digestive health.

“Adequate stomach acid is very important for protein digestion and low stomach acid can slow down protein digestion,” she adds. 

Protein powder is generally digested in the same way as dietary protein. However, the absorption rate may differ depending on the type of protein powder and what it’s mixed with.

For example, whey protein is absorbed faster than casein protein. And since liquids digest faster than whole foods, a protein powder consumed without additional fat or fiber will be absorbed faster than dietary protein.