What happens to excess protein intake in the body?

Excess protein intake in the body is converted into fat and stored. When the body consumes more protein than it needs for immediate energy and muscle repair, the surplus amino acids are not stored as muscle tissue; instead, they undergo deamination, where the amino group is removed. The remaining carbon skeletons can then be converted into glucose through gluconeogenesis or into fatty acids. These fatty acids can subsequently be stored in adipose tissue for later use. This metabolic process highlights the body's efficiency in managing macronutrients, ensuring that any excess consumption is utilized or stored appropriately, often in the form of fat if not needed for energy or tissue maintenance.

In contrast, while some might think excess protein could be excreted without impacting health, this is not entirely accurate since while the body does excrete unused nitrogen through urine, chronic excessive protein intake can strain the kidneys in some individuals. Storage as muscle tissue primarily requires resistance training stimulus, and protein is used in emergencies mainly for amino acids to sustain critical bodily functions rather than as a primary fuel source under normal conditions.