Food is composed of many different types of nutrients, and the bigger nutrients are called macros. “Macro generally means ‘large enough to see,’ as opposed to micro — it’s an imperfect distinction but good enough,” says David Katz, MD, the president of the True Health Initiative and the founding director of the Prevention Research Center at Yale University in New Haven, Connecticut.
The three main macronutrients in our food are carbohydrates, protein, and fat.
“Carbohydrates are the preferred source of energy for the body, especially the brain,” says Levinson. “Carbohydrates break down into glucose in the body, and glucose goes from the bloodstream to the body’s cells to help them function,” Levinson adds. This in turn aids bodily functions and provides energy for physical activity, according to the Harvard T.H. Chan School of Public Health.
On the other hand, proteins are known as the building blocks of life, according to MedlinePlus. Protein is the main component of muscles, bones, organs, skin, and nails, says Levinson. “Protein is essential for growth, development, repair, and maintenance of body tissues,” she adds.
Dietary fat, meanwhile, provides the body with energy, aids cell function, protects organs, and keeps the body warm, notes the American Heart Association. “Fats also play a role in hormone production, cell growth, energy storage, and the absorption of many vitamins — aka micronutrients,” adds Levinson.
If these macronutrients sound like a big deal, it’s because, well, they are. “Since the macronutrients are the source of all protein, fat, and carbohydrate in the body — and since they are delivered along with the micronutrients we require — their role in the body is, simply, everything,” says Katz. “They are the stuff of which we are made; they are the fuel on which we run,” Katz says.
And as for micronutrients, they’re the smaller vitamins and minerals that also play an important role in your body, according to the Cleveland Clinic, helping with everything from digestion to brain function.