The satiety effect that protein provides has been known for a while, but not very well understood. A study published in the Cell Press journal Cellhelps explain how this muscle building macronutrient helps you feel less hungry.

Researchers analyzed the mu-opioid receptors (MOR) in lab mice. They are located in the portal vein’s wall, a primary vessel for draining blood from the digestive tract. When stimulated, MOR enhances food intake. But protein consumption blocks MOR signaling.

True Strength Moment: Active adults who care about how they look and watch what they eat don’t typically feast until their mid-section bulges. But they do experience a feeling of fullness, or satiety. It turns out that the protein you rely on for muscle recovery also helps suppress appetite and control caloric intake.