Macronutrients, or “macros,” are the building blocks of nutrition. You probably know them better as carbohydrate, protein, and fat. Macros are the nutrients you need in large amounts, as they provide your body with the calories it needs to function. (Micronutrients include vitamins and minerals, and although they’re essential for good health, they don’t provide any calories and only trace amounts are needed.)

It can get a little confusing, because people often refer to foods as macros: saying bread and pasta are “carbs,” and talking about meat as “protein.” Those foods contain more of that specific macronutrient than the others. But macros are just the individual elements, and most foods are made up of a blend of all three—pasta actually contains a little protein, and meat definitely has fat!  Understanding macros can help you lay a solid foundation for a balanced diet.

Carbohydrate: Provides fuel, the energy for your body and brain. It’s found in all plant foods, like grains, fruits, vegetables, and legumes, and also milk and yogurt.

Protein: Helps to build and repair your muscles, organs, skin, blood, and different chemicals, like hormones, in your body. It’s found in large amounts in meat, poultry, fish, legumes, dairy, tofu, and eggs, and in smaller amounts in nuts, seeds, and whole grains.

Fat: Insulates and protects your bones and organs, acts as backup fuel for energy, and helps in brain development. Healthy, unsaturated fats are found in olive oil, avocados, nuts, seeds, and fatty fish, like salmon, sardines, and mackerel. Unhealthy saturated fats are found in high-fat beef, pork, butter, full-fat dairy, and processed foods, like cookies and donuts.

The numbers aren’t set in stone, but you do need to consume a certain amount of each macro within a range. The flexibility allows you to pick a style of eating that suits your needs, food preferences, and health goals. The USDA recommends the following healthy ranges.

Carbohydrate: 45 to 65 percent

Protein: 10 to 35 percent

Fat: 20 to 35 percent

Not sure where your eating habits put you? The food logging feature in the Fitbit app can estimate your macronutrients when you log items from the food database! At the end of each day, you can view an estimate of daily totals as percentages, as well as in grams. Which makes aiming for a particular ratio of carbs to protein to fat to build a balanced diet a lot easier.

If you’ve ever cut back on carbs to try to lose weight, carb loaded before a marathon, or upped your protein intake to put on muscle, you’ve been playing with your macros. Working within the recommended ranges above, there’s room to maneuver your macros for different outcomes. For example, if you’re trying to lose weight, eating fewer carbs and more protein may help—you could try aiming for the lower end of the range for carbohydrate, with 45 percent carbs, 25 percent protein, and 30 percent healthy fats, for example. Or, if you’re an athlete and need to fuel up for an intense training schedule, you can shoot for a higher percentage of carbs, making the ratio look more like 55 percent carbs, 20 percent protein, and 25 percent healthy fats. Just remember, these numbers don’t reflect the space each food takes up on your plate, but rather the numbers you’ll see when you log your meals.

Again, because most foods contain a mix of carbs, protein, and fat, you can’t completely cut one macro from your diet. That would impossible, not to mention unhealthy—sorry, zero-carb followers!

Bodybuilders in particular are known for counting their macros, relying on eating trends, like If It Fits Your Macros (IIFYM) or Flexible Dieting, which focus on manipulating macronutrients to achieve weight loss or gain muscle. But people following those diets often lose sight of what’s healthy and what’s not. Your macronutrient distribution could look the same, whether you’re eating pizza, burgers, and donuts, or minimally processed veggies stir-fries and grain bowls. Quality wins over quantity when it comes to your health, so don’t get so caught up when measuring your macros that you miss out on the foods your body really needs.

Even if you’re not signing up for a powerlifting competition or an endurance race, and you don’t want to micro-manage your macros, it’s still smart to see where your numbers fall. Getting colorful fruits, veggies, whole grains, healthy fats, and lean protein on your plate is the most important thing, and balancing macronutrients is just one more way to think about sticking to a healthy eating plan. So try food logging for a few days to see how your macros measure up.