What is meant when you say that CHO and fat are protein sparing?

When we say that carbohydrates (CHO) and fats are protein-sparing, it means that when these macronutrients are adequately supplied in the diet, the body can use them for energy instead of breaking down proteins for fuel. This is important because it helps preserve muscle mass and allows proteins to be utilized for their primary roles in building and repairing tissues, rather than being used as an energy source. Essentially, a diet rich in CHO and fats can help maintain protein's critical functions in the body.