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Macronutrients 101

What are macronutrients and why do they matter?

The prefix ‘macro-’ means large. The word ‘nutrient’ signifies a substance that provides nourishment essential for growth and maintenance of life. Together, ‘macronutrients’ are the nutrients that the body requires in large quantities in order to function optimally.

There are 3 macronutrients:

  1. Carbohydrates

  2. Protein

  3. Fat

Each of these macronutrients provides energy for your body in the form of calories.


The most common and abundant forms of carbohydrates are sugars, fibers, and starches. They’re classified according to how many sugar units are combined in one molecule. When you consume carbs, your body metabolizes them into glucose, which is the main fuel source for the body and the brain. The main function of carbohydrates is to provide energy, but they also play an important role in the structure and function of cells, tissues, and organs.

Low-carb fad diets seem to be popping up left and right, and while it’s true that eating excess carbs will cause weight gain, you’d be doing significant damage to your body by avoiding carbohydrates all together. In fact, more of your daily caloric intake should come from carbs than anything else. Each gram of carbohydrate has 4 calories.

However, it’s important to note that the amount of carbohydrates consumed in the diet is less important than the type of carbohydrates that are being consumed. There are healthier options than others. Focus on nourishing your body with unprocessed whole grains, vegetables, fruits, and legumes instead of highly processed and refined white bread, pastries, and soda. Just remember that carbs are an essential part of your diet. Your body NEEDS them.


Proteins are large molecules composed of long chains of amino acids that are the building blocks responsible for health and growth of muscle, hair, nails, skin, eyes, and other organs. The body creates enzymes, hormones, and antibodies using amino acids and even serve as a means of transportation for some molecules in the body.

The body’s prefered method of getting energy is first from carbohydrates, then from fats, and finally protein as its last resort. Amino acids aren’t a significant source of fuel for energy metabolism unless during a state of starvation. Proteins assisting in energy production is called gluconeogenesis.

Protein in adequate amounts is necessary to build, repair, and maintain tissues and is absolutely essential for building lean muscle mass. This is why you hear weightlifters preaching the importance of eating protein. A high-protein diet also promotes higher satiation, helping to avoid overeating and ultimately aid in weight loss. Of course this does not mean to consume an unlimited amount of protein because, just like anything else, too much protein will be stored as fat.

Protein provides the body with 4 calories per gram and is found in meats, fish, eggs, cheese, nuts, and seeds just to name a few.


Fat is the third of the three main classes of food and source of energy in the body. Fats help the body use some vitamins, absorb other nutrients, nourish the nervous system, maintain cell structures, keep the skin healthy, and serve as your body’s largest energy storage.

Dietary fats include saturated fat, which come mainly from animal sources, and unsaturated fat, which are plant-based. There is a sort of fat you should avoid at all costs: trans-fat. Trans-fat is unnatural and is created to add to foods primarily to increase shelf life. It has many adverse effects on health, so steer clear of processed foods because they likely contain trans-fat.

Healthy fats are found in things like nuts, meats, olive oil, and avocado. Fat weighs in at 9 calories per gram, making it the densest source of energy in the diet. Though fat is an essential component of the diet, it’s important to have an awareness of the quantity of high-fat foods you’re consuming, since it is so calorie dense.

This week, when consuming food, actively think about what you’re putting into your body. If you don’t already think of the foods you eat in terms of what nutrients they’re made of, then now is a great time to start. Your body will thank you.

So, now you have a basic understanding of what the macronutrients are and the functions they serve inside of the body. But what ratio of carbohydrates, proteins, and fats should you be eating? Stay tuned for next week’s blog!


*I am not a nutritionist. Please consult your physician regarding changing your diet.

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