Protein intake and digestive health

Increasing protein intake can lead to digestive issues such as bloating and foul-smelling gas. This occurs when the small intestine cannot fully absorb the increased amount of protein, allowing undigested molecules to reach the colon. There, bacteria ferment amino acids—specifically those containing sulfur found in animal proteins—producing gases like hydrogen sulfide.

Digestive discomfort is often exacerbated by a simultaneous reduction in dietary fiber. A lack of fiber slows intestinal transit, providing bacteria more time to produce sulfurous gases. Additionally, protein supplements may contribute to bloating if they contain lactose, artificial sweeteners, or thickeners that are difficult to digest.

To mitigate these effects and support gut health, experts suggest consuming foods that provide both protein and fiber. Legumes, such as lentils, are highlighted as effective options because they offer high-quality plant protein alongside soluble and insoluble fibers, which help regulate intestinal transit and support a healthy microbiota.