To continue nutrition education for National Nutrition Month, I wanted to focus on macronutrients. What are they? What do they mean for you? How can you use them to create a healthy diet? These are questions that will be answered within this blog.
It is always helpful to start by getting back to the basics of nutrition. Nutrition is the science of food and its relationship to health. Nutrients are chemicals in foods that are used by the body for various processes including growth, energy, and maintenance. Nutrients can’t be synthesized by the body and must be obtained from the foods we eat and are therefore considered essential. Macronutrients are those nutrients that are required in large amounts. However, an excess intake of macronutrients can lead to obesity and weight gain, so it is important to understand how much of each is needed to avoid unwanted weight gain.
What are macronutrients?
Macronutrients can be broken down into 3 main categories: carbohydrates, protein (including essential amino acids), and fats (including essential fatty acids). Carbohydrates, fats, and protein are sources of energy that have a set number of calories per gram.
- Carbohydrates are broken down into two categories: simple or complex carbohydrates. Simple carbohydrates are those that will increase blood glucose levels rapidly and are generally small molecules. These are things like sugar, sweets, refined grains, and processed foods. Complex carbohydrates are larger molecules that increase blood glucose levels more slowly but for a longer time. These are things like whole grains and fruit. Because carbohydrates are the main source of energy for your body, it is important to have more complex carbohydrates versus simple carbohydrates because it will fuel your body for a longer period.
- Proteins, which are broken into peptides and amino acids, are required for tissues maintenance, replacement, function, and growth. If the body is not getting enough calories from dietary sources or tissue stores, like fat stores, protein can be used for energy. Of the 20 amino acids, 9 are essential, which means that they cannot be synthesized in the body and must be obtained from the diet.
- Fats, which are broken down into fatty acids and glycerol, are required for tissue growth and hormone production. Essential fatty acids are omega 3 and omega 6 fatty acids and are needed by the body for biological functions.
How do macronutrients contribute to a healthy diet?
Macronutrients are important because they make up the energy component of your diet. Other areas of your diet that don’t contribute to energy are micronutrients, water, and macrominerals. Micronutrients are things like Vitamin B, folate, thiamine, Vitamin A, and Vitamin D. Macrominerals are things like sodium, chloride, calcium, potassium, phosphate, and magnesium. It is true that these 3 categories are important to maintain a good nutrition and health status, but they are not needed in large volumes like macronutrients are.
Carbohydrates, protein, and fat all contribute a certain amount of energy, what we call calories, per gram. Carbohydrates and protein each have 4 calories per gram, while fat has 9 calories per gram. Therefore, foods high in fat contain a much higher number of calories per serving.
Breaking down these categories into a manageable diet is where a dietitian can help you determine the amount of calories you should be consuming on a daily basis depending on your age, height, current weight, and medical history. However, for educational purposes, I will discuss how much the average American who is 40 years of age, at a normal weight for height, and has no metabolic medical conditions, should be aiming for when it comes to caloric and macronutrient intake each day.
This individual would need about 2000 calories a day to maintain a healthy weight. The rule for most average people in terms of macronutrients is to aim for 50% carbohydrates, 30% protein, and 20% fat. Again, this is something that can be tweaked when working with a dietitian who knows your specific needs. When looking at 2000 calories a day, that means 1000 calories are coming from carbohydrates, 600 calories from protein, and 400 calories from fat. Then by using the calories per gram of each macronutrient as discussed above, we can determine the grams of each needed each day: 250 grams of carbohydrates, 150 grams of protein, and 44 grams of fat.
These numbers become more manageable than looking at 2000 calories and trying to determine what to eat to be within the number but still get a variety of foods. Carbohydrates, protein, and fat are all listed on the nutrition facts labels as well, which makes it easy to track the grams you are eating of each macronutrient within each meal and also within each day.
The Takeaway
Creating a healthy diet can be challenging when you must start from scratch and don’t know where to begin. By using your calorie goal and then breaking it down into macronutrients and how many grams you should be having of each macronutrient, that gives you the ability to create a diet that fits your needs and lifestyle. By using the macronutrients, you can look at nutrition facts labels and count the number of carbohydrates, fat, and protein to determine if that food is a good choice for you.
For example, when looking at a nutrition facts label that states the product has 20 grams of fat, 10 grams of carbohydrate, and 2 grams of protein, then you should be able to determine that this product wouldn’t necessarily fit well into your macronutrient groups very well since it has more fat than protein and carbohydrates. Since fat is the lowest percentage of the three categories, you might want to choose another product or make another healthier substitution. This is how macronutrients can help you make healthier choices, stay within your calorie target, and get a variety of foods and nutrients.
I do encourage you to seek out a dietitian if you are trying to start a new diet, lose weight, or are trying to manage a chronic condition or disease. They will be able to work with you to set individualized goals that meet your expectations and fit into your lifestyle.
References:
- USDA National Agriculture Library. Macronutrients. Accessed March 21, 2022. https://www.nal.usda.gov/legacy/fnic/macronutrients.
- Harvard T.H. Chan School of Public Health. The Nutrition Source: Carbohydrates. Accessed March 21, 2022. https://www.hsph.harvard.edu/nutritionsource/carbohydrates/.
- Youdim, Adrienne (2019). Overview of Nutrition. Merck Manual. Accessed March 21, 2022. https://www.merckmanuals.com/professional/nutritional-disorders/nutrition-general-considerations/overview-of-nutrition#v881321.