https://avitahealth.org/health-library/macronutrients-a-simple-guide-to-macros/
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Your body needs these nutrients in larger amounts in order to function properly as macro means large. In addition, all of these nutrients provide your body with energy measured in the form of calories or kcals. There are three types of macronutrients: carbohydrates, proteins, and fats.
- Carbohydrates contain 4 kcal per gram
- Proteins contain 4 kcal per gram
- Fats contain 9 kcal per gram (this is roughly double the amount found in the other two macros)
Along with energy, all of these macronutrients have specific roles in your body that allows you to function properly.
Carbohydrates
All carbohydrates are eventually broken down into glucose, which is the main energy source for your body. In fact, specific organs, such as your brain, need glucose in order to function properly. Your body can make glucose out of necessity from proteins using gluconeogenesis. Beyond being your main energy source, there are carbohydrates that help synthesize specific amino acids (protein building blocks) and allow for consistent bowel movements. Fiber is a type of carbohydrate that cannot be broken down by your GI tract. Therefore, this nutrient does not give you energy, but it does help rid your body of waste and keeps your intestinal tract healthy. Carbohydrates are not all created equally. Some are considered simple carbohydrates and others are complex.
- Simple carbohydrates are easy for your body to breakdown for energy or glucose. They have 1-2 sugar molecules and are found in items that are usually sweet such as honey, table sugar, syrup, agave nectar, molasses, milk/yogurt, and fruit. Fruit does contain a natural sugar called fructose, however, fruit also has vitamins and minerals (these are your micronutrients: nutrients needed in small amounts), phytochemicals (not a needed nutrient, but can have positive effects on health), and fiber. Fiber is not digested and therefore, increases the amount of time needed to break down the food item.
- Complex carbohydrates take more time for your body to breakdown. They are long strands of sugar molecules strung together and typically have a savory taste. They are found in foods such as starches and grains: rice, pasta, bread, and starchy vegetables (potatoes, peas, corn). Other plant based foods such as non-starchy vegetables (beans, nuts, and seeds) contain carbohydrates, but in lower amounts. Complex carbs normally contain fiber unless they have been processed, where the grain has been stripped of its bran (outer coating), which gives us white bread, white pasta, white rice, etc. These types of carbs become easier for your body to digest. Even though they are not sweet they will release glucose quickly just like a sweet simple carbohydrate.
Protein
Protein allows your body to grow, build and repair tissues, and protect lean body mass (your muscle mass). Protein is composed of amino acids. Amino acids are the building blocks of protein. There are 2 types of amino acids: non-essential and essential. Non-essential amino acids are not required to be consumed through the diet as your body can actually make these. Essential amino acids are required through your diet. Essential amino acids can either be used on their own or in some cases they are transformed into a non-essential amino acid. Protein rich foods include meat, poultry, fish, egg, milk, cheese, or other types of animal by-product foods. These protein sources contain all of your essential amino acids. This does not mean you have to eat animal foods to be healthy. You can get the proper amino acids from eating a variety of plant protein sources such as beans, lentils, nuts, seeds, and soy as well as lower amounts in grains, vegetables, and fruits.
Fat
Fat allows you to store energy, cushion organs, make certain hormones, absorb fat soluble vitamins, and helps with cell membrane integrity. There are three types of fat: trans fat, saturated fat, and unsaturated fat.
- Trans fat should be cut out of the diet. Most trans fat comes from hydrogenating or adding hydrogen molecules to unsaturated fats. This produces a hydrogenated oil. These can be found in margarine, shortening, baked goods, doughs, and fried foods. If you see trans fat on the label it should be avoided.
- Saturated fat does not have any bends, caused by double bonds, in the molecule because it is saturated in hydrogen molecules. In large amounts, saturated fat is known to increase cholesterol levels and can increase your risk for heart disease. Decreasing the amount of saturated fat in your diet can be beneficial. Saturated fat is found mostly in animal sources with high fat contents such as fatty beef, lamb, pork, poultry with skin, lard, cream, butter, full fat cheese, and dairy. The American Heart Association recommends 5-6% of your daily kcals come from saturated fat; meaning if your kcal needs are 2,000 per day, only 120 kcals should come from saturated fat. 120 kcals/9 kcals/g = ~13 grams of saturated fat per day. It is recommended that you decrease saturated fat intake and lean towards more healthy fats, known as unsaturated fats.
- Unsaturated fat has at least one double bond causing bends in the molecule. These are harder to stack and, therefore, are usually found in a liquid state at room temperature. The number of double bonds allows for the naming of unsaturated fats. Mono unsaturated fats have one double bond while Poly unsaturated fats have multiple or many. Unsaturated fats are known as the healthy fat as they can decrease your risk for heart disease. These healthy fats originate from plant sources such as avocados, nuts and nut butters, seeds, olives, and oils (olive, canola, safflower etc.). They can also be found in animal sources such as fatty fish including salmon, mackerel, sardines, tuna, and herring.
Fat gets a bad reputation because it is the highest in kcals and certain types of fat are not good for us, but if you can focus on the type of fat and amount of fat, it is instrumental to a healthy diet.
The recommended amounts of these different macronutrients are usually referred to as macronutrient split. A good place to start is using the USDA recommendations:
- Carbohydrates: 45-65%
- Protein: 10-35%
- Fat: 20-35%
