Macro-nutrients in the diet

Macro-nutrients in the diet

How should macronutrients be distributed in the diet?

How should macronutrients be distributed in the diet?

Excessive body fat caused by an imbalance between energy intake and expenditure is currently the most important nutritional problem in developed countries and is rapidly becoming a global epidemic. Some well-intended guidelines are highly prescriptive in terms of energy intake or servings per day of each food group. A fundamental problem is that even the healthiest combination of foods consumed in slight excess, by only a few percent, over an extended period of time, will lead to overweight.

The AMDR (Acceptable macronutrient distribution range) reflects a range of intakes of an energy source (i.e., macronutrients [protein, amino acids, carbohydrates, fat, and fatty acids]) associated with the risk of chronic disease. The ranges take into account the need to ensure adequate intakes of the essential nutrients contained in such energy sources.

Acceptable Macronutrient Distribution Ranges*

1-3 Year             4-18 Years           >19 Years
Protein 5-20                    10-30                    10-35
Carbohydrate 45-65                  45-65                     45-65
Fat 30-40                  25-35                     20-35
Added sugars                               ≤25% of total calories


*Modified from Food and Nutrition Board, Institute of Medicine: Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids, Washington, DC, 2002/2005: National Academies Press.


Fats in the Daily Diet

The ADA (American Diabethis Association) /DC (Dietitians of Canada) /ACSM (American College of Sports Medicine) position stand notes that fat, a source of energy, essential fatty acids, and fat-soluble vitamins, is important in the diets of athletes and recommends that athletes should obtain approximately 20% to 35% of total energy intake from fat, which is the AMDR. The position stand also notes that consuming less than 20% of energy from fat does not benefit performance. As with healthy carbohydrates, diets should focus on healthy fats. In general, the goal is to replace saturated fats, sugars, and refined starches with monounsaturated and polyunsaturated fats, such as olive oil, canola oil, and unsalted nuts.

Carbohydrates in the Daily Diet

The ACSM, ADA, and DC note that during times of high physical activity, energy and macronutrient needs, especially carbohydrate, must be met. AMDR for carbohydrate is 45% to 65% of daily energy intake.

Protein in the Daily Diet

The recommended dietary allowance (RDA) for protein is based on the body weight of the individual and the amount needed per unit body weight is greater during childhood and adolescence than during adulthood. The adult RDA for protein is 0.8 g/kg body weight. The AMDR for protein is 10% to 35% of daily energy intake. Whether athletes require more than the RDA for protein is debated.

How much protein can the body use in a single meal for muscle-building?

It has been proposed that muscle protein synthesis is maximized in young adults with an intake of ~ 20–25 g of a high-quality protein; anything above this amount is believed to be oxidized for energy or transaminated to form urea and other organic acids. to maximize anabolism one should consume protein at a target intake of 0.4 g/kg/meal across a minimum of four meals in order to reach a minimum of 1.6 g/kg/day. Using the upper daily intake of 2.2 g/kg/day reported in the literature spread out over the same four meals would necessitate a maximum of 0.55 g/kg/meal. High protein meals can increase MIT (meal-induced thermogenesis) and fullness and reduce hunger compared with high carbohydrate meals.


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