HUMAN NUTRITION

Detailed explanation-1: -Carbohydrates provide 4 calories per gram, protein provides 4 calories per gram, and fat provides 9 calories per gram.

Detailed explanation-2: -Fat has more than twice as many calories per gram as carbohydrates and proteins. A gram of fat has about 9 calories, while a gram of carbohydrate or protein has about 4 calories.

Detailed explanation-3: -Of the three major calorie sources (fat, protein and carbohydrate), fats have the most calories per gram making fat-rich foods the most common calorie-dense foods.

Detailed explanation-4: -Of these, cells typically use lipids, carbohydrates, and proteins for energy. Lipids have the most calories per gram of the macromolecules. Lipids provide cells with 9 calories of energy per gram, while proteins and carbohydrates provide 4 calories per gram.

Detailed explanation-5: -Because lipids include a high percentage of C-H bonds, which store chemical potential energy more effectively than other molecules, fats have a substantially higher energy density than carbohydrates. Hence, fats contain more energy per gram than carbohydrates.