Macronutrients are compounds that your body needs in large quantities to function correctly. You can find them on the carbohydrate, protein and fat lists of food labels. Over time, a severe deficiency of any of these nutrients can affect energy levels, growth and, eventually, your ability to survive.
Carbohydrates are the body's main source of energy. The Institute of Medicine recommends that between 45 and 65 percent of daily calories come from this nutrient. Your body converts carbohydrates into sugars that can be burned immediately for energy or stored in the muscles. Without the right amount of carbohydrates, you may feel tired and weak, since your body should look for other less efficient sources of energy. A severe carbohydrate deficiency can prevent the kidneys, brain and heart from receiving the energy needed to function. Without enough fiber, a type of carbohydrate that your body can not digest, you may experience constipation and hemorrhoids. Fiber deficiency also increases the risk of developing certain types of cancer and heart disease.
While saturated and trans fats can increase the risk of developing heart disease, the healthy fats present in plants, called unsaturated fats, are indispensable for many bodily functions. Without the proper amount of fat, it is possible to dry the hair and skin. You may experience hunger more often because fats take more time to leave the stomach than proteins or carbohydrates, so they provide a feeling of fullness. To be able to absorb vitamins A, D, E and K and certain nutrients called carotenoids, you must consume a diet of dietary fats. Omega 3 fats, present in fatty fish, nuts (walnuts) and flaxseeds, reduce the risk of developing heart disease. If you do not get enough of these healthy fats, you may have an increased risk of developing coronary artery disease. The Institute of Medicine recommends consuming between 20 and 35 percent of your daily calories from healthy fats.
Your body needs the amino acids that come from proteins to promote growth, tissue repair, immunity, the production of hormones and enzymes and the preservation of lean muscle mass. The Institute of Medicine recommends consuming between 10 and 35 percent of daily calories from protein. Protein deficiencies are unusual in the United States, but they can cause muscle wasting, diarrhea, atrophy of growth, reduced immunity, protruding belly and fatigue.
Most diets that include a variety of foods from different groups, such as dairy, meat, vegetables, fruits and grains, provide the right amount of macronutrients. If you follow a diet that restricts the intake of macronutrients, such as a diet low in carbohydrates or fats, consult your doctor to find out if you get adequate amounts of macronutrients. In many cases, these strict diets are unsustainable because they cause fatigue or nutrient deficiencies. Vegetarians and vegans should pay special attention when planning a diet that includes adequate amounts of protein from non-animal sources, such as beans, nuts and seeds.