Macronutrients are nutrients that the body needs in large amounts to provide the body with energy (calories). Not only is energy needed for physical activity, but also for everyday activities like talking, reading, and eating. It’s also necessary to perform vital functions like keeping your heart beating.
The three macronutrients are carbohydrates, protein and fat. Each macronutrient has a different role in the body, which is explained in more detail below. In general, all foods have different macronutrient compositions, and it’s essential to get a balance of all three throughout the day.
Carbohydrates – the main source of fuel for your body and brain.
Carbohydrates are the preferred fuel for tissues and organs, and the only fuel sources for our red blood cells. Your body is able to store carbohydrates as glycogen in your muscles as a source of energy when blood glucose is low. If carbohydrate intakes are too low, the body breaks down muscles and organs to create useable fuel.
The Recommended Dietary Allowance (RDA) for carbohydrates is 130 grams a day, which is the minimum amount required to optimally fuel the brain, red blood cells, and nervous system. Low carbohydrate intake can lead to poor performance in physical activity and increased risk of injury. You will see a decrease in energy levels, strength, stamina and decision making when carbohydrate intakes are too low.
Although carbohydrates are fuel, not all carbohydrates are created equal. Simple carbohydrates are easily digestible, and provide a quick release of energy. Complex carbohydrates take longer to break down, resulting in a gradual release of energy.
Sources of simple carbohydrates
– Fruits, some vegetables, some beans, and dairy are good sources
– Sweeteners, candy, jellies, jams, and refined flour are sources to limit due to lack of nutritional value
Sources of complex carbohydrates
– Bread, rice, pasta, beans, whole grains, vegetables
– Aim to make half your grains whole grains
Protein – the building blocks for our body’s structure.
Protein is used to build and repair your body’s tissues, enzymes, and hormones that regulate metabolism and growth. Unlike carbohydrates and fat, protein cannot be stored in the body, so it is important to eat enough daily.
Protein is made up of amino acids. There are 20 amino acids – 9 of which are essential and must be consumed through diet. Since protein cannot be stored, any excess amino acids in the body are converted into glucose and stored as glycogen in the muscles or converted to fatty acids and stored as fat in the body. Your body can only use a certain amount of protein at a time, so protein is most effectively used when spread throughout the day. This can be achieved by including a source of protein at every meal or snack. Protein can also help with satiety because it takes longer than carbohydrates to digest.
Sources of protein
– Meat, poultry, fish, beans, lentils, soy, eggs, nuts, seeds, nut butter, diary, and even whole grains
Fat – the helpers and protectors of your body.
Fat is essential for many of your body functions. It is what helps to maintain your body temperature, supports immune function, cushion and protects your vital organs, facilitates nerve transmission, assists in vitamin absorption, and provides an energy source for low-intensity exercise.
Your body uses fat as fuel for low-intensity activity to spare glucose for your brain and red blood cells. Fats are found in a variety of foods, and the types of fat in foods vary. Unsaturated fats are considered the “healthy” fats because they don’t increase your risk for heart disease, and can help to lower you cholesterol. Omega-3 and omega-6 fatty acids are unsaturated fats that we must consume through our diet because our bodies do not produce them. They play a role in regulating our immune systems. Omega-3 fatty acids are essential for our vision and nervous system, and have been linked to reducing inflammation. Saturated fats are mostly found in animal sources, but can be found in plant sources (coconut and palm oil). Saturated fats increase risk for heart disease and raises cholesterol, and has been linked to inflammation in the body.
You should aim to limit saturated fat to <10% of your total calories. Trans fat is synthetically made to make foods more shelf stable. Trans fat has been shown to increase LDL and decrease HDL. Due to the negative impact on heart health, trans fats should be limited.
Sources of unsaturated fats
– Oils, nuts, avocado, fatty fish, and seeds
Sources of saturated fats
– Meat, poultry, butter, margarine, lard, baked goods, coconut and palm oil
The 2015 Dietary Guidelines for Americans recommends a macronutrient distribution of: 45-65% carbohydrates, 10-35% protein, 20-35% fat – less than 10% from saturated fats.
These are recommended ranges for the average American. The percentages of macronutrients needed are different person to person based on height, weight, age, lifestyle, gender, and health. This web-based daily nutrient calculator can help to estimate your daily recommended intakes. Don’t forget to concentrate on the quality of the food itself if monitoring macronutrient intakes. Eat a balanced combination of nutritious foods from all categories that contribute to your overall health.
