Why is the DIT of protein so high? In short, protein contains nitrogen, which needs to be removed before amino acids can be put to use. Once amino acids are freed, they’re used for energy-demanding processes such as protein synthesis and de novo gluconeogenesis (DNG). Studies looking at the latter found 20 to 33 percent of calories from ingested protein were lost, depending on the nutritional state of subjects—20 percent when fed, and 33 percent when glycogen depleted (ref. 1,12).
