Nutrition Diving Deeper: Macronutrients

Written by: Elizabeth Fay, MS, RD, CNSC

Registered Dietitian, Certified Nutrition Support Clinician


Macronutrients are the group of nutrients that provide us with energy throughout our day. The three macronutrients in our diet include carbohydrates, protein, and fat. These three nutrient categories are essential in our diet to provide us with balanced nutrition and energy. Depending on lifestyle factors, genetics, and medical conditions, we all require varying amounts of each macronutrient, but in the end, we cannot live without any single macronutrient category. Let’s discuss each macronutrient, their impact on the body, and how much we may need every day.

Carbohydrates provide us with high energy substrate and are the preferred fuel for the body, including the brain. Our muscle and liver cells use carbohydrates in the form of glucose and these sites store carbohydrates in the form of glycogen. When our glycogen stores run low, our body can break down fat storage for fuel or utilize our muscle tissue (which is our body’s protein pool) as a source of energy. Of course, we want to preserve our muscle tissue in our body and avoid our metabolism from shifting its use of carbohydrates as fuel to our muscles as fuel. Some symptoms of inadequate carbohydrate in the diet can be seen as low blood sugar, decreased energy, bad breath, nausea, and constipation. Carbohydrates are found in all 5 food groups: fruits, vegetables, grains, protein, and dairy. Many people think of grains as rich carbohydrate sources, but fruit, starchy vegetables, beans, legumes, yogurt, and milk are all great sources of carbohydrate. No matter what the food group, carbohydrates are referred to as complex or simple. Complex carbohydrates offer starch and fiber, while simple carbohydrates provide sugar. Starch and fiber help slow down our digestion, keep us feeling full for longer, help to reduce our cholesterol, and maintain blood sugar control, so choosing complex carbohydrates is a healthy choice. No matter what the type of carbohydrate, each gram of carbohydrate provides 4 calories. When looking at a Nutrition Facts Label, you will see Total Carbohydrates printed. Total carbohydrates will be listed in grams and nested beneath this category, you will find Dietary Fiber and Total Sugars. Under Total Sugars, the Nutrition Facts lists how many grams of those sugars were added to the product under Added Sugars. This is important to take note of because the term “sugar” usually brings a negative thought to mind. However, sugar naturally found in fruit provides different nutritional benefits than added sugars in soda. General carbohydrate recommendations are 45-65% of total calories. For example, on a 2,000 calorie meal plan, the recommendation would be 225-325 grams carbohydrate per day. If you are active, you may require the upper end of this range, whereas if you are trying to control high blood sugar, you may aim for a lower goal within this range. Talk with your Registered Dietitian to determine your individual carbohydrate needs.


Protein is an essential macronutrient for development. Protein is made up of single amino acids, all of which the body uses in different ways. The body can make some of these amino acids on its own, but 9 of the 20 amino acids must be consumed in the diet. Unfortunately, our body doesn’t have a storage pool for protein, like it does for carbohydrates. We must consume adequate amounts of protein on a regular basis to meet our protein needs. If we consume more protein than we need one day, then the protein is converted to fat as excess energy and stored as fuel for later use. If we do not consume enough protein on a regular basis, we will continue to fall short and we may experience symptoms of hunger, muscle loss, edema/swelling or fluid retention, hair loss, inadequate growth, and decreased strength. Protein is found in all 5 food groups as well, but its richest sources are in the protein, dairy, and grains food groups. Protein foods are rich in protein as demonstrated by its food group name, but a variety of foods in this food group may surprise you. Both animal- and plant-based foods are excellent sources of protein. Animal-based protein examples are common, such as fish, beef, and poultry. Plant-based foods rich in protein include beans, nuts, soy, and seeds. Not all 20 amino acids are found in every protein food, so eating a variety of protein-rich foods helps to ensure adequacy. Just like carbohydrates, each gram of protein provides 4 calories. On the Nutrition Facts Label, Protein is lised in grams. General nutrient recommendations for protein are 10-35% for adults. As an example, a 2,000 calorie meal plan would recommend 50-175 grams of protein per day. Very active adults and pregnant women may aim for the higher end of this protein range, whereas adults with chronic kidney disease not yet receiving dialysis may restrict protein to the lower limit. Discuss your individual protein needs with your Registered Dietitian.


Fat completes our discussion of macronutrients and this nutrient group is vital, despite its often overlooked benefits. Our body requires that we consume adequate fat in our diet for normal development, to maintain skin integrity, optimize brain health, and to use as an excellent energy source. Fat is the most energy-dense macronutrient. For every gram of fat, 9 calories are provided. There are certain types of fat that are essential in the body, because just like some amino acids, the body cannot make these specific fats. There are many types of fat in the diet, including saturated, trans, polyunsaturated, and monounsaturated. These different types of fats can have both healthful and unhealthful nutritional impacts on the body. The least healthful types of fat are saturated and trans, therefore it is recommended we reduce intakes of these types of fats. More healthful options are polyunsaturated and monounsaturated fats to optimize heart health. Fat is a rich energy source and if we consume too much fat than our body requires, then our body optimizes this intake and stores it as a fat reserve in the body. This fat reserve is called adipose tissue. It’s important that we find an adequate balance to meet our fat needs just right.

For those who consume a fat free or very low fat diet, signs and symptoms of essential fatty acid deficiency include scaly skin, suboptimal growth, and delayed wound healing. Recommendations for fat intake are between 20-35% of total daily calories for most adults. On a 2,000 calorie meal plan, recommended fat intake would be 44-78 grams per day of total fat. Monitor your fat intake by reading the Nutrition Facts Label. Just like carbohydrates, Total Fats are listed on the label and then subdivided into the different types of fat within the product. Saturated fat and trans fat will always be listed on the food label, but manufacturers may choose to include the amount of polyunsaturated fats and monounsaturated fats for additional information. Fat is found in all 5 food groups, but in very little amounts in most fruits, vegetables, and grains. Fat is found in many foods in the protein and dairy food groups. Heart healthy, fat-rich foods include nuts, seeds, and avocados. Discuss your own fat requirements with your Nuleeu Registered Dietitian.


Leave a Reply