For the best grocery experience,
try our mobile app.


How the Body Uses Essential Nutrients

How the Body Uses Essential Nutrients

Carbohydrates, proteins, and fats are the three macronutrients that provide our bodies with energy.  Macronutrient means that we need them in larger amounts than the micronutrients, which are vitamins and minerals. 

The human body is very adept at making do with creating energy from whatever calories it is provided with.  After all, man once survived on seeds and berries that could be gathered or the occasional meat from a successful hunt.  In today’s world, calories are cheap and very readily available.  Understanding the role of each macronutrient and knowing how each is used by the body can help us make better choices when it comes to our own diets.


The role of carbohydrates is to provide energy, as they are the body’s main source of fuel, needed for physical activity, brain function and operation of the organs. All the cells and tissues in your body need carbs.  Once in the body, carbohydrates are quickly and easily converted to fuel known as glucose. Glucose enters the circulatory system, causing blood glucose levels to rise.  Carbohydrates are readily available for energy because the body’s cells gobble up this bounty of glucose more quickly than they do protein or fat.  The glucose that is not used for energy is stored in the liver and muscles for later distribution throughout the body in the event that blood sugar levels drop too low.  After the body has used the available glucose for energy and has stored all it can in the liver, the excess is stored as fat.



Protein is the building block of the body.  It is vital in the maintenance and repair of body cells and tissues.  Hair, skin, eyes, muscles, cartilage, and organs are all made of protein.  We also use protein to make enzymes, hormones, and other body chemicals.  Unlike carbohydrates and fats, the human body is not able to store extra protein for use as protein.  Children require more protein than adults because they are still growing and building new protein tissue.  Once the necessary amount of protein has been used for tissue maintenance and other necessary functions, it can be used as a source of energy.



Virtually all foods contain some fat.  We need some fat in our diet to survive.  However, as is true for both carbohydrates and protein, the intake of excess calories from fat will be stored as excess body fat.   Fat is a concentrated source of energy. One gram of fat has 9 calories, which is more than double the amount of calories from carbohydrates and protein, which contain 4 calories per gram.   Because fat is high in calories, you need to limit your diet to 20 to 35 percent calories from fat.  Fat is important for insulation, protection of internal organs, and for the absorption of some vitamins.  Vitamins A, D, E, and K, called the fat-soluble vitamins, rely on fat for absorption in the body.

Nancy Hintze

About the author

Nancy Hintze, originally from St. Louis, Missouri, began her career as a Foods and Nutrition teacher in Lehi, Utah in 2003. At the time she began teaching middle school students about nutrition, she weighed 286 pounds. She quickly became aware that if she expected her students to believe her, she had to be an example of what she taught. Over the course of the next several years, as she eliminated 125 pounds by changing what she ate and how she cooked, Nancy became passionate about sharing her healthy lifestyle keys with her students and their families. Along the journey of her transformation, she also became an avid chef with a zest for good old fashioned food preparation with a modern twist – healthy ingredients and ease of preparation.

Nancy is a licensed Family and Consumer Sciences teacher as well as a certified L.E.A.N Health Coach. She has developed and produced Community Nutrition Fairs, mentored students in the Fuel Up to Play program and accompanied one of her students to represent Utah in the National Fuel Up to Play summit in Washington, D. C. In addition, she has coached individual clients to achieve greater levels of personal wellness. And now we have the privilege of announcing Nancy as our very own Culinary Nutritionist here at Reams.

When she’s not sharing her passion for great eating with others, you can find her in her vegetable garden, or knitting or sewing, reading a great novel, hanging out with one of her 21 grandchildren or on the road in the RV that she and her husband love to travel in.