Macronutrients are nutrients that provide calories (energy). Nutrients are substances needed for growth, metabolism, and other functioning. Since “macro” means large, macronutrients are nutrients needed in large amounts. There are three categories of macronutrients:
While each of these macronutrients provides calories, the amount of calories that each one provides varies. One gram of carbohydrate or protein provides 4 calories per gram. One gram of fat provides 9 calories per gram. If you looked at the Nutrition Facts label of a food product and it said 12 grams of carbohydrate, 0 grams of fat, and 0 grams of protein per serving, you would know that this food has about 48 calories per serving (12 grams carbohydrate multiplied by 4 calories for each gram of carbohydrate = 48 calories). The only other substance that provides calories is alcohol, which provides 7 calories per gram. Alcohol, however, is not a macronutrient, because we do not need it for survival.
Macronutrients are not the only things that we need for health. Our body also needs water and micronutrients. According to the 2004 Dietary Reference Intakes (DRIs), adult men need about 3.7 liters of water per day, and adult women need about 2.7 liters of water per day. Micronutrients are nutrients that our bodies need in smaller amounts, and include vitamins and minerals.
This document is a source of information only, and is not medical advice.