Nutrition Facts

The Basics of Macronutrients

Why it’s important to understand macronutrients
If you understand macronutrients, you’ll have an easier time sorting through the various diet programs on the market and selecting the one that’s right for you.

What are macronutrients?
Macronutrients are the nutrients found in food that supply our bodies with calories or energy. Macro means large. A macronutrient is a nutrient that the body requires in large amounts. The energy absorbed through consumption of macronutrients fuels growth, metabolism and other body functions.

It is important to realize that no food by itself contains every nutrient the body requires for good health. Also, many different combinations of food can provide us with the proper mix of nutrients we need – and in the right amounts.

The core macronutrients
The foundation of a good diet is found in the three core macronutrients: carbohydrate, protein and fat. The amount of calories supplied by the different macronutrients is as follows:

  • Carbohydrate: 4 calories/gram
  • Protein: 4 calories/gram
  • Fat: 9 calories/gram

Why is this useful to know?
If you’re in the supermarket trying to select a packaged product, you can look to the Nutrition Facts label to learn its macronutrient content. If the product has 10 grams of carbohydrate, 0 grams of fat, and 0 grams of protein per serving, that tells you eating a meal of the food will provide you with 40 calories. (Remember, carbohydrates have 4 calories per gram, so you multiply the 10 grams of carbohydrates by 4 calories for each gram)

In addition to carbohydrates, proteins, and fats, one other substance provides calories: alcohol. Alcohol supplies 7 calories per gram. While alcohol is a source of calories and energy, it is not a macronutrient because our bodies don’t require it to survive.

Let’s look more closely at the core macronutrients.


We require carbohydrates in larger amounts than proteins or fats. The USDA’s Dietary Reference Intakes recommends that we get 45 to 65 percent of our calories from carbohydrates.

Where carbohydrates are found
The primary source of carbohydrates is starchy foods (think grains and potatoes), fruits, milk, and yogurt. Carbohydrates are found in lesser amounts in vegetables, beans, nuts, seeds and cottage cheese contain carbohydrates.

Carbohydrates and fiber
Some foods contain carbohydrates that our digestive systems are unable to break down and absorb. Research has shown that diets high in fiber can help reduce obesity and cholesterol. Fruits, vegetables and whole grains are some of the foods that are high in fiber.


The USDA’s Dietary Reference Intakes recommends that we get 10 to 35 percent of our calories from protein. The body uses protein for a number of purposes, including growth and tissue repair. When carbohydrate is unavailable, it will use protein for energy.

Where proteins are found
Foods that supply protein include meats, poultry, fish, meat substitutes, cheese, milk, nuts and legumes. Starchy foods and vegetables supply proteins in smaller amounts.


The USDA’s Dietary Reference Intakes recommends that we get 20 to 35 percent of our calories from fat. People concerned about their weight should rightly be wary about the amount of fat they consume, but some fat is necessary for survival. Of all the energy sources available to our bodies, fat is the most concentrated. If you eat a lot of fat, you are more likely to gain weight than if you eat a lot of carbohydrate or protein

Where fats are found
Foods that supply fat include meat, poultry, nuts, milk products, butters and margarines, oils, lard, fish, grain products and salad dressings.

Three main kinds of dietary fat
It is helpful to know the main dietary fat types. They are: Saturated fat, unsaturated fat and trans fat.

Saturated fat is associated with raised blood cholesterol levels. Food especially high in saturated fat includes butter, margarine, meat and dairy products.

Unsaturated fat is typically found in liquid form. Unlike saturated fat, unsaturated fat does not raise blood cholesterol levels. Canola and olive oil have the highest percentage of monounsaturated fat compared with other cooking oils. Safflower and corn oil have the highest percentage of polyunsaturated fat.

Trans fats are unsaturated fats (oils) that have been artificially hydrogenated (hydrogen molecules are added to the fatty acid chains) to make them solid in texture, much like saturated fats. Food manufacturers do this because trans fats provide more satisfactory cooking results and have an appealing mouth feel. Unfortunately, the body recognizes trans fats as a saturated fats, so they contribute to raised cholesterol levels and heart disease.

Some research has shown that replacing saturated and trans fats with monounsaturated fats can promote weight loss. The British Journal of Nutrition has published two studies on the subject, found here and here.

Don’t forget about water and micronutrients
Macronutrients are nutrients required in large amounts to supply the body with calories and energy. But the body also needs other things for survival. It needs water in large amounts (6-8 glasses daily) and it needs micronutrients, which are nutrients required in smaller amounts. Micronutrients include the vitamins and minerals the body uses to produce enzymes, hormones and other substances essential for proper growth and development.