We all know that the foods and beverages we consume fuel our bodies and minds. However, these also provide the building blocks for our bodies. The nutrients we consume fall into two primary categories: macronutrients (“macros”) and micronutrients (“micros”).
By volume, we need far more macros than micros to maintain our bodies, hence the names.
The 3 main macronutrients with caloric value are fat, carbohydrates and protein.
All three of these provide calories: you need to consume a mix of these in order to maintain your body and energy levels. How much of each you need to reach your total daily energy requirement is the subject of fierce debate in the nutrition community. The purpose of this piece is not to weigh in on that debate, but rather to provide an outline of each macronutrient and its role in human nutrition.
Carbohydrates, or “carbs” as they are commonly known, are an excellent source of energy. Many popular diet plans reduce or eliminate carb intake as a means for weight loss. This theory is based on carbs’ high caloric content. Refined sugar, for example, is a pure carbohydrate.
Carbs can be simple or complex. Simple carbohydrates are quickly absorbed by the body and converted to energy. Complex carbs, for reasons not explored here, are more slowly converted to energy in the body. As a result, many nutritionists suggest favoring complex carbohydrates over simple carbohydrates in your diet. The theory behind this advice is that simple carbs cause blood sugar spikes that can result in cravings when blood sugar levels later come down, while complex carbs deliver energy in a steadier fashion that avoids sugar spikes.
Foods high in carbs include corn, breads, sugars (including high fructose corn syrup), rice and potatoes.
Fats come in two basic forms – saturated and unsaturated. Saturated fats typically come from animal sources (meat and dairy), and are solid at room temperature. Unsaturated fats predominantly come from plant sources, and are liquid at room temperature. Studies have shown a link between diets high in saturated fats and cardiovascular disease.
Fats have enjoyed a resurgence in favor among nutritionists. Consider, for example, the avocado. Once considered a food to avoid at all costs due to its high fat content, has become one of the most popular foods in health circles. This is because in recent years, nutritionists have come to recognize that healthy fats have numerous benefits, and can provide a more advantageous source of calories than a diet high in carbohydrates. For instance, olive oil is an unsaturated fat with widely recognized health benefits.
Foods high in saturated fat include high fat dairy like cream cheese and butter, and meats like bacon. Foods high in unsaturated fats include nuts and vegetable oils.
Protein is a critical element of any diet, and one of the most valuable resources in natural ecosystems. Proteins are complex molecules built of amino acids. There are a variety of aminos, and no one protein source is complete, meaning that it provides the full complement of amino acids necessary for healthy body function. While protein is most commonly associated with animal sources like meat and dairy, one of the most complete sources of protein is actually soy.
Protein in crucial in building muscle. Your protein requirements will vary based on your activity levels and body composition goals. Bodybuilders typically strive to consume 0.8-1 gram of protein per pound of body weight each day. However, if you are not actively seeking to build muscle, your protein requirements are far lower. Indeed, if you follow a diet that is very high in protein, you must be mindful of your water intake. Failure to maintain adequate hydration while consuming a large amount of protein can cause kidney damage, which should be avoided.
Foods high in protein include meat, nuts, beans, and soy.
Macronutrients and Metabolism
The human body prefers obtaining calories from macronutrients in the order presented above:
This order of preference is the foundation of many fad diets including Atkins and South Beach. By filling your caloric needs with fats and protein and avoiding carbohydrates, the theory goes, your body will be prompted to begin accessing its stored fat energy to meet your daily needs.