Your friend always refers to meat as protein. you try to correct her by stating that:

Practically all foods contain mixtures of the energy-yielding nutrients.

Explanation:

Meat doesn't just contain protein, so it's wrong to refer to meat as protein, because that's not the only nutrient it has. Virtually all foods contain energy-producing nutrient mixtures. In the case of meat, in addition to the high protein content, meat has significant values of lipids, fat-soluble vitamins (A, D, E and K), water-soluble B-complex vitamins (thiamine, riboflavin, nicotinamide, pyridoxine, pantothenic acid, acid folate, niacin, cobalamin and biotin) and some vitamin C. It also has a variable content of iron, phosphorus, potassium, sodium, magnesium and zinc. In addition, 70-75% of its constitution is made up of water.