What Are Macronutrients? Understanding Carbs, Fat and Protein — Registered Dietitian Columbia SC

What Are Macronutrients?

Macronutrients are nutrients in food that break down to provide your body with energy (aka calories). The three macronutrients in food are carbs, fat, and protein. Technically, alcohol is also a macronutrient as it provides the body with energy, but for obvious reasons that’s not included in the three principle macronutrients, and we won’t discuss it in this post 🙂

Humans don’t photosynthesize. We don’t fill up our tank with gasoline or plug into batteries. We eat food, and that’s how our body obtains energy to breathe, walk, talk, think, and do all our daily activities. Macronutrients are the compounds that provide your body with energy. They break down into smaller units that are absorbed into the bloodstream during digestion, and eventually distributed to cells so they can do their thing.

The term “macro” means large, meaning these nutrients are needed in large amounts, and that they are larger chemical compounds. This is opposed to micronutrients, like vitamins and minerals, which are also important, but needed in smaller amounts for human functioning. Also, while micronutrients are needed in various metabolic reactions to convert macronutrients to energy, and in other bodily processes, they do not break down to provide the body with energy.

What are Macronutrients: Carbohydrates

Carbohydrates are the body’s main source of fuel. They break down into monosaccharides – simple sugars that include glucose, fructose, and galactose (although often these are grouped together and referred to as glucose). There are three main types of carbohydrates found in food: sugars, starches and fiber. Most carbohydrate containing foods will have a combination of these three. I’ll also note, fiber is a type of carbohydrate that does not break down to provide the body with energy, but it does play other important roles, including aiding digestion, supporting healthy blood sugar levels, and promoting satiety.

Carbohydrates are the body’s main source of fuel, including the only source of fuel your brain can use. Technically, your body has a backup fuel source through ketosis, which produces energy your brain can use in the absence of adequate carbohydrate. A good thing because otherwise we would go braindead if you went too long without eating or went on a low carb diet! However, this is a backup system designed to protect you against starvation and death, and has side effects including loss of muscle mass, headache, fatigue, nausea, cramping and funky breath/body odor. Because carbs are so essential, one doesn’t need to go into ketosis to have side effects of inadequate carbohydrate intake. Not eating enough carbs can lead to difficulty concentrating, fatigue, anxiety, mood swings (hello hanger), and extreme hunger as your body signals it’s internal fuel tank is low.

Carbs are found in the following foods*:

• Grains – anything made with flour (i.e. bread, pasta, baked goods, tortillas, cereals, crackers, pretzels, etc), rice, quinoa, oats, corn, millet, teff, barley, buckwheat, etc.

• Beans and pulses – black beans, chickpeas, lentils, butter beans, pinto beans, etc.

• Starchy vegetables – potatoes, sweet potatoes, winter squash, parsnips, etc.

• Milk and yogurt

• Fruit

• Table sugar and other sweeteners (i.e. maple syrup, honey, agave, etc.)

• Non-starchy vegetables – non-starchy vegetables like tomatoes, zucchini, lettuces, etc. contain very small amounts of carbohydrate, and mostly fiber, but I’ll include them here