Kara Morton is a third year medical student at University of Louisville School of Medicine. You can follow her on instagram.

Three macronutrients make up the food we eat: carbohydrates, protein, and fat. They are different because they each have a unique chemical structure that allows them to be utilized for various processes in the body. There is not one macronutrient that is better or healthier than the others. In essence, all three are present in healthy food, and all three are necessary for vital bodily functions!

CARBOHYDRATES

It is recommended that 45% to 65% of your daily calories come from carbohydrates. That means between 225 and 325 grams for an average 2000 calorie daily intake. This is equal to between 900 and 1300 calories from carbohydrates every day!

Carbohydrates are the body’s preferred source of energy. They can be broken down immediately after a meal to provide power for metabolic functions. They can also be stored away in the liver, the muscles, and fat cells for easy access at a later time.

The healthiest carbohydrates are known as “complex carbohydrates.” These are found in whole, natural foods like vegetables, fruits, beans, and whole grains like brown rice and oats. These are the foods that are also high in fiber.

Fiber is a vital complex carbohydrate. Fiber bulks up our food to keep us full longer. Fiber is also critical for proper digestion and gut health! At least 25 to 30 grams of our daily carbohydrates should come from fiber, but most Americans barely get 15 grams!

It’s important to notice that not all carbohydrates are created equal! Simple carbohydrates, which often come from processing and refining, have been stripped of their fiber and proper nutrients. Simple carbohydrates include white breads, table sugar, desserts, and packaged snack foods. Complex carbohydrates, such as whole-grain breads, whole fruit, and plenty of vegetables, should be chosen over simple carbohydrates as often as possible!

PROTEINS

It is recommended that the average person eats 0.8 grams of protein per kilogram of body weight daily (0.36 grams of protein per pound of body weight). Based on this recommendation, a healthy-weight adult woman needs 46 grams of protein per day, and a healthy-weight man needs about 56 grams per day. To calculate your daily protein recommendation, use this formula:

Weight in pounds x 0.36 = daily grams of protein

Dietary protein is used in our bodies for building, maintaining, and repairing body tissues. Protein is not an efficient source of quick energy like carbohydrates. Our bodies are also very efficient when it comes to using our dietary protein for its metabolic functions; this is one of the reasons the recommended daily protein intake may seem so low!

Contrary to popular belief, meat and eggs are NOT the only source of protein in a healthy diet. These food groups provide plenty of protein; however, plant-based protein can be found in soy products, beans, nuts, seeds, whole grains, and even vegetables! Fun fact: one pound of broccoli contains more protein than one pound of steak!

Most Americans get double the amount of protein than they truly need! This excess protein can often not be stored efficiently by our bodies and is filtered out through our kidneys and into our urine. High-protein diets, especially from animal sources, have also been associated with higher risks of developing kidney disease, heart disease, and some cancers.

FATS

It is recommended that 20% to 35% of your daily calories come from fats. This is equal to between 44 and 77 grams of fat for an average 2000 calorie daily intake. There are nine calories per 1 gram of fat (compared to 4 calories per 1 gram of carbohydrates and protein), making fat the highest-energy macronutrient.

Fats can are divided into three groups: unsaturated, saturated, and trans fats. 

Unsaturated fats are liquid at room temperature and are the primary fats in nuts, seeds, certain fruits like avocados and olives, and the oils made from them. Heart-healthy omega-3 fats are included in the unsaturated fats group. Unsaturated fats should make up the bulk of your daily fat intake! 

Saturated fats are solid at room temperature and are the primary fats in butter, lard, heavy creams, and most animal-based foods (meats, poultry, fish). Too much dietary saturated fat has been linked to an increased risk of cardiovascular disease, including heart attack and stroke. It is recommended to keep your intake of saturated fat under 10% of your daily calories, which equals about 22 grams daily.

Trans fat is the unhealthiest type of fat. Trans fats are created by partial hydrogenation, which is a process that involves adding hydrogen ions to the chemical structure of the natural fat. Partial hydrogenation creates a type of fat that is shelf-stable, which is useful for keeping packaged foods from expiring, but bad for our bodies. This incomplete hydrogenation process makes trans fats nearly impossible for our bodies to break down and significantly raises the risk of developing plaques in the arteries. Trans fats can be found in fried foods, packaged baked goods, certain forms of margarine, and other packaged snacks. Trans fats are not healthy or safe at any dietary level and should be avoided.

Cholesterol is a type of fat that comes from animal sources such as meat, poultry, and eggs. As humans, we are also able to make our own cholesterol! Our bodies use this endogenous cholesterol for hormone production, cell integrity, and energy storage. Consuming too much cholesterol can result in elevated blood levels and cholesterol deposition in the walls of our arteries. This process contributes to atherosclerosis and heart disease. To lower your risk of these diseases, try to minimize dietary cholesterol by eating fewer meats and eggs, or none at all.

Additional Resources

For more detailed information, visit any of the following pages:

• The American Heart Association diet and lifestyle webpage 
• An ethical plant-based vegan diet, 
• The American College of Lifestyle Medicine 
• Academy of Nutrition and Dietetics
• USDA’s 2015-2020 Dietary Guidelines for Americans