Introduction to Macros: Understanding Macronutrients and Their Role in Nutrition

Key Takeaways

• Macronutrients, including carbohydrates, proteins, and fats, are the nutrients your body needs in the largest amounts. 
• Each macro plays an important role in energy, metabolism, and overall health. 
• Understanding each macro's calorie content and function can help you balance the three that will support your health goals. 

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Have you ever heard someone say they’re “counting macros” or “hitting their macros” and wonder what that means? Macronutrients, aka macros, are the nutrients your body needs in the largest amounts, and they play a big role in your energy levels, metabolism, blood sugars, and overall health. 

Understanding how the three main macronutrients —protein, carbohydrates, and fat —work together in your body can help you make informed food choices and achieve your health and wellness goals. In this article, you’ll learn what macronutrients are and the role each one plays in your nutrition and overall health, as well as strategies for balancing your macros. 

What Are Macronutrients? 

Macros are the main nutrients your body needs in large amounts. They’re essential, meaning that our body cannot produce them independently, and they provide the calories (energy) we need to live. They support body processes like growth, repair, movement, insulation, and hormone production. On the other hand, micronutrients include vitamins and minerals, which are needed in much smaller amounts and do not contribute significant energy. The three main macronutrients are carbohydrates, fat, and protein. 

Each macro plays a unique role in your health and is responsible for a wide variety of essential functions. Fat is the most calorie-dense macronutrient, providing nine calories per gram, while protein and carbohydrates provide four calories per gram. Combined, they create a balanced diet supporting a healthy, well-functioning body. 

Carbohydrates: The Body's Primary Energy Source

Carbohydrates are your body’s primary source of energy. When you eat carbs, such as bread, pasta, fruit, milk, beans, and vegetables, your body breaks them down into glucose, a simple sugar that contains four calories per gram. Glucose then travels through your bloodstream and is used by your cells as fuel, especially by your brain, which relies heavily on glucose to function properly. While your body can switch to using fat and protein for energy if it does not have enough carbohydrates, glucose is preferred under normal conditions.¹

Carbohydrates include simple sugars, complex sugars, starches, and fiber. Sugars and starches are broken down into glucose and used for energy, but fiber isn’t fully digested and doesn’t contribute the same amount of calories. Instead, fiber serves other functions, such as helping to regulate blood sugar and cholesterol levels, reducing fat absorption, feeding gut bacteria, and promoting regular bowel movements. 

Proteins: Building Blocks of the Body 

Proteins get a lot of credit for building muscle, and while this is an important function, it’s far from the only role protein plays in the body. Contributing four calories per gram, protein is made up of 20 amino acids that are essentially the building blocks of life. Protein is responsible for building and repairing tissues, including muscle tissue, supporting immune function, and is needed for the production of the hormones and enzymes needed to carry out virtually every biochemical process in the body.²

Protein is essential because nine of the 20 amino acids can only be obtained through food, while the others can be generated in the body as needed. Protein-rich food sources include animal products such as meat, fish, eggs, and dairy, as well as plant-based protein sources like soy, legumes, grains, nuts, and seeds.  

Fats: Essential for Energy and Cellular Functions 

Fat is much more calorie-dense than carbohydrates or protein, providing nine calories per gram. While we may need less fat than the other macronutrients, including it in our diet is still essential. Fat is used for long-lasting energy, hormone production, and support and insulation of our cells. It is also needed for the absorption of many micronutrients and other compounds; not eating enough fat can lead to low levels of fat-soluble vitamins, such as A, D, E, and K. 

We eat several different types of dietary fat, including saturated, unsaturated, and trans fatty acids. Trans fatty acids, which often come from the hydrogenation of plant oils and are found in small amounts in ruminant animal products (like beef and dairy), are the one type of fat that research has proven, without a doubt, is detrimental to our health.³

Based on current research, saturated fats in tropical plant oils like coconut and palm oil and animal products should account for 10% or less of your total energy intake. Unsaturated fats are found in fatty fish and plants, such as avocados, nuts, seeds, and oils like olive oil, avocado oil, and canola oil. These fats contain essential polyunsaturated fatty acids, including omega-3s and omega-6s, as well as monounsaturated fats. These fats include reducing inflammation, improving heart health markers, and supporting brain health.⁴

Caloric Values of Macronutrients 

All macronutrients provide calories.

• Carbohydrates: 4 kcal/gram
• Protein: 4 kcal/gram
• Fats: 4 kcal/gram

Because fat is much more calorie-dense than protein and carbs, a small amount adds up quickly. Adding small amounts of fat to your meals is beneficial in terms of the health benefits you’ll reap from the fat itself and the satiety it provides, but too much may lead to unwanted weight gain. Understanding the calorie contribution of each nutrient can help you create meals and snacks that align with your goals. 

Balancing Macronutrients for Optimal Health 

While the amount you need may vary, the most recent USDA-assigned Acceptable Macronutrient Distribution Ranges (AMDR) for adults is:⁵

• Protein: 10–35% of your daily calories
• Carbohydrates: 45–65% of your daily calories
• Fat: 20–35% of your daily calories

This range is not as useful as understanding your specific nutrient needs based on your current body weight or goal weight, as following percentages of your total calories may leave you deficient in some macronutrients while eating too many of others.⁶ If you’re unsure what macronutrient distribution is right for you, consult with a registered dietitian to help. 

There is no one-size-fits-all approach to balancing your macros. The amount of each macronutrient you need depends on your health goals, activity levels, and any medical conditions. For example, someone training for a marathon will need more carbohydrates. In contrast, someone with diabetes who is managing their blood sugars may benefit from a diet higher in protein, with a lower percentage of carbohydrates. 

Practical Tips for Incorporating Macronutrients into Your Diet 

While percentages and counting grams of macros can help you gain awareness, eating an overall healthy diet isn’t always practical or necessary. Including a mix of each macronutrient in your meals and snacks will help you feel energized, satisfied, and provide your body with the nutrients it needs. While many foods include all three macronutrients, they often have one that is dominant. Here are some tips to get started: 

• Carbohydrates: Choose fiber-rich carbs like whole grains, fruits, vegetables, beans, and lentils. These foods are slow-digesting, keeping your energy levels steady and supporting gut health and digestion. 
• Protein: Aim for a variety of proteins, including meat, fish, eggs, Greek yogurt, tofu, seeds, nuts, and beans. Mixing plant and animal proteins and eating a variety of them will make sure you’re getting enough of all nine essential amino acids in your diet. 
• Fat: Include mostly unsaturated fats from fish, nuts, seeds, and avocado. These fats support your brain and heart while helping you feel full and satisfied. 

The Bottom Line

Macronutrients are the foundation of your diet, giving your body the energy and support it needs to function. Understanding how carbs, protein, and fat work together to fuel your body can help you create meals that help you feel full and satisfied and provide the energy and support you need to reach your health goals. 

Learn More About How to Improve Blood Sugar Health With Signos’ Expert Advice

Understanding how Macros work is just one part of the puzzle. See how Signos can help improve your health with an in-depth understanding of how your body reacts to the food you eat and metabolizes glucose.