Macronutrients include carbohydrates, protein and fat, and are found in all foods. They provide the energy necessary to fuel daily metabolic processes and physical activities. Some people may want to calculate macronutrient intake in adherence with special diets.
Check nutrition labels. Identify the number of carbohydrate, protein and fat grams in each serving. Write the grams for carbohydrates, protein and fat per serving on a piece of paper.
Multiply the grams of carbohydrates by four to obtain the calories per serving from this macronutrient. Multiply the grams of protein by four to calculate calories per serving. Multiply the grams of fat by nine for calories per serving.
Identify your total calorie needs and write it down. Multiply your daily calorie needs by .45, or 45 percent, to identify the minimum calories from carbohydrate recommended by the U.S. Department of Agriculture. Multiply your daily calorie needs by .10, or 10 percent, for the minimum calories from protein. Multiply your daily calorie needs by .20, or 20 percent, to calculate the minimum calories from fat recommended by the USDA.
Write down your total calorie needs. Multiply your daily calorie needs by .65, or 65 percent, to identify the upper limit of carbohydrate intake recommended by the USDA. Multiply your daily calorie needs by .15, or 15 percent, to get the recommended upper limit of protein. Multiply your daily calorie needs by .35, or 35 percent, for the upper limit of fat intake recommended by the USDA.
Stay within the recommended limits for each macronutrient. Do not reduce or eliminate an entire class of macronutrients from your diet because it can cause nutrient deficiencies.