Collectively known as "macronutrients," carbohydrates, protein and fat make up the dietary triad that's essential for your diet. While each macronutrient plays an important role in the body, carbohydrates usually make up the bulk of your diet, followed by fat and finally protein.
The average healthy person should consume 10 to 30 percent of daily calories from protein, 45 to 65 percent from carbohydrates and 25 to 35 percent from fat.
Overall Caloric Intake
When you break down your diet, the first thing you should look at is your overall caloric intake. That tells you how much energy you're consuming during the day.
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Once you know how many calories you eat in the typical day, you can figure out how many calories you're consuming from carbohydrates, fat and protein. Ideally, 10 to 30 percent of your total calories should come from protein, 45 to 65 percent from carbohydrates and 25 to 35 percent from fat, according to guidelines from the Office of Disease Prevention and Health Promotion. However, these numbers only work if you consistently eat your recommended calories per day.
Protein for Building
Every cell in your body contains protein, as it's the main building material that your body uses. Your hair, muscle, bone and skin all contain protein, according to Harvard School of Public Health. When you eat protein, your body breaks it down into amino acids. It takes the amino acids and combines them to form new protein in different parts of your body.
Consuming 10 to 30 percent of your daily calories from protein should provide enough amino acids to keep your body functioning properly. If you go to the gym or play sports you should consume more protein than the average person. Exercise breaks down muscle and connective tissue, which needs to be replaced. Thirty-five percent of your daily calories should come from protein, according to the British Nutrition Foundation.
Carbohydrates for Energy
According to a 2018 study from Nutrition Today, carbohydrates are the best source of fuel for your body if you're active. Your body breaks carbs down into glycogen and glucose, which go out into your bloodstream, liver and muscles to fuel many functions in your body. Your brain uses glucose for energy as well as your muscles, which is why you need to consume it throughout the day.
You can get energy from fat, but it's harder for your body to digest. Fiber is a type of carbohydrate that's difficult to digest and keeps you feeling full so you eat less. There's also some evidence that fiber can lower your risk for heart disease, type 2 diabetes and colon cancer, according to Harvard School of Public Health.
Fat for Nutrients
Consuming at least 20 percent of your daily calories through fat should provide the minimum amount of fat-soluble vitamins and fatty acids to stay healthy, according to a 2017 study published in Nutrition Journal. Some vitamins can only survive if they're stored in fat cells, so you need to eat fat to get these vitamins in your diet.
Essential fatty acids, such as omega-3s, are an important part of a healthy diet. They can help lower your risk for heart disease and irregular heartbeat, according to an article from MedLine Plus. National Health Services recommends eating seafood twice per week to increase omega-3 intake.
The RDA of fat is capped at 35 percent to ensure that you're not consuming too many calories. You should track the number of grams of fat per day that you consume because it's calorie-dense. Each gram is 9 calories. You'll also avoid eating too much saturated fat, which can increase your risk for coronary heart disease, according to a 2017 study published in the Annals of Nutrition and Metabolism.
- American Heart Association: Know Your Fats
- Nutrition Journal: A healthy approach to dietary fats: understanding the science and taking action to reduce consumer confusion
- Annals of Nutrition and Metabolism: Saturated Fat Consumption and Risk of Coronary Heart Disease and Ischemic Stroke: A Science Update
- MedLine Plus: Facts about polyunsaturated fats
- NHS: Fat: the facts
- British Nutrition Foundation: Protein intake for athletes and active adults: Current concepts and controversies
- Harvard HSHP: Protein
- HSHP: Fiber
- Nutrition Today: High-Quality Carbohydrates and Physical Performance
- British Nutrition Foundation: Carbohydrate