Heart disease, cancer, and strokes are the three leading causes of death in the United States, and diabetes also ranks in the top ten. All four of these chronic diseases have significant links to nutrition and account for about two-thirds of the nation's 2 million deaths each year. Wise food choices, made throughout the lifespan, can support a person's ability to meet physical, emotional, and mental challenges and to enjoy freedom from disease.
Every day your body requires a certain amount of energy from carbohydrates, protein and fats to function properly. Because no single food provides all of the nutrients your body needs, eating a variety of foods ensures that you get all of the necessary nutrients and other substances associated with good health.
Eating well doesn't have to be complicated. Unless you need a special diet for a specific health problem, the best approach is to follow national dietary recommendations. These recommendations have evolved over the years to keep pace with an expanding scientific knowledge on how diet can affect health and prevent disease.
The most recent recommendations come from the National Academy of Sciences' Institute of Medicine. These guidelines are significantly different from those of the past, particularly in regard to carbohydrates and fat. More fat is allowed, and carbohydrates have a lower minimum percentage — from 55 percent to 45 percent. This is due to research indicating that people with a certain body type and metabolic profile may benefit from fewer carbohydrates and more monounsaturated fat.
Your body burns (metabolizes) carbohydrates, protein and fat to produce energy and perform other necessary functions. This energy is measured in calories.
Your energy needs vary considerably according to your activity level, body size, sex and age. For example, an older, petite, sedentary woman may need only 1,600 calories a day, but a 25-year-old woman of the same size who is very physically active may need 1,800 to 2,200 calories a day.
On average, daily calorie goals are as follows:
1,600 — children ages 2 to 6, most women and some older adults 2,000 — average adult 2,200 — older children, teenage girls, active women and most men 2,800 — teenage boys and active men
Protein: 10 percent to 35 percent of total calories
Protein is essential to human life — every cell in your body contains it. Your skin, bones, muscle and organ tissue all contain protein. It's found in your blood, hormones and enzymes as well.
Protein is also a nutrient found in many foods. Legumes, poultry, seafood, meat, dairy products, nuts and seeds are your richest sources of protein. Grains and vegetables supply small amounts. Remember to choose your sources of protein wisely. Many high-protein foods are also high in fat and cholesterol.
The amount of protein your body needs varies depending on your weight. For example, a 140-pound woman needs about 51 grams of protein a day, and a 175-pound man needs about 64 grams a day — based on the estimated requirement of 0.364 grams per pound (0.8 grams per kilogram) of body weight. However, most Americans typically eat far more protein than they need. Your body stores the extra calories from protein as fat.
Even if you don't eat any animal protein, you can easily get enough protein as long as you include in your diet some protein-packed plant-based foods, such as beans, lentils, tofu or tempeh.
Carbohydrates: 45 percent to 65 percent of total calories
Carbohydrates are your body's main energy source, the primary fuel for your cells. Carbohydrates are starches and sugars. Starches — found primarily in bread, rice, pasta, cereals and vegetables — are complex carbohydrates. Sugars — found in fruits, milk and foods made with sugar, such as candy and other sweets — are called simple carbohydrates or simple sugars.
Approximately 45 percent to 65 percent of your total daily calories — at least 130 grams — should come from carbohydrates. Complex carbohydrates and sugars from fruit and milk are preferred to simple sugars from candy and sweets. Your body absorbs complex carbohydrates more slowly than it absorbs simple sugars, providing you with more energy for a longer period of time. In addition, complex carbohydrates, fruit and milk provide more nutrients and fiber than sweets do.
Some foods have sugar added to them during processing or preparation. Foods containing added sugars generally provide many calories, but their nutrient content — vitamins and minerals — may be quite low. In the United States, regular (non-diet) soft drinks are the top source of added sugars. Other major sources include candies, cakes, cookies, fruit drinks and dairy desserts, such as ice cream.
Fat: 20 percent to 35 percent of total calories
Unlike protein and carbohydrates, fat is an extremely concentrated form of energy that contains little water. Among its many important tasks are aiding in the absorption of many essential vitamins, helping maintain the structure and function of cell membranes and assisting your body's immune system. But too much fat can have a negative effect on your health, such as increasing your risk of heart disease, diabetes and obesity.
The food you eat has several different kinds of fat, including:
Saturated fat. This type of fat can be found in butter, cheese, whole milk, cream, eggs, meat, poultry, chocolate, coconut, palm oil, lard and solid shortenings. Polyunsaturated fat. Vegetable oils, such as safflower, corn, sunflower, soy and cottonseed oils, are high in polyunsaturated fat. Trans fat. Most margarines and shortenings are high in trans fat. Commercial baked goods and fried foods, such as doughnuts or French fries, also have significant amounts of trans fat. Monounsaturated fat. Foods high in monounsaturated fat include avocados, nuts, and olive, peanut and canola oils.
About 20 percent to 35 percent of your daily calories should come from fat. To reduce fat in your diet, choose lean foods — such as fish, skinless white poultry and low-fat dairy products — and eat more foods naturally low in fat, such as fruits, vegetables and whole grains.
Saturated fat: No more than 10 percent of total calories
Saturated fat is the main dietary culprit in raising your blood cholesterol and increasing your risk of coronary artery disease. Therefore, limit your daily intake of saturated fat to no more than 10 percent of your total calories.
To reduce your saturated fat intake, limit meat, butter, cheese, whole milk, cream and eggs in your diet, along with foods made from chocolate, lard, solid shortenings, and palm and coconut oils.
Cholesterol: No more than 300 milligrams (mg) a day
All foods from animals contain cholesterol. Concentrated sources include meats, egg yolks and whole-milk products.
Limit cholesterol, but don't overemphasize its significance. The primary dietary determinant of high blood cholesterol is saturated fat. For some people, though, dietary cholesterol has a significant impact on their level of blood cholesterol. Limiting cholesterol intake is a good idea for anyone trying to keep his or her cholesterol level down.
Sodium: No more than 2,400 mg a day
Only small amounts of sodium occur naturally in food. In fact, most of the sodium you eat is added during food processing and preparation. Canned soups and vegetables and many boxed or frozen processed foods are very high in sodium, as are processed meats, such as bacon, sausage and ham.
Healthy adults need only a small amount of sodium daily. The recommended daily limit is 2,400 mg. This is the amount found in about 1 teaspoon of salt. Most Americans consume about 4,000 to 5,000 mg of sodium a day. Too much sodium may contribute to a rise in your blood pressure, putting you at risk of heart attack and stroke.
Control sodium by limiting processed foods. Also cut back on the salt you add while cooking and at the table. As you use less salt, your preference for salt will decline, allowing you to enjoy the taste of the food itself.
Dietary fiber: 21 to 38 grams a day
Fiber is the part of plant-based foods that your body doesn't digest and absorb. Two types of fiber can be found in food: soluble and insoluble.
Insoluble fiber adds bulk to your stool and helps prevent constipation. It also reduces your risk of colon and rectal cancers. It's found mainly in vegetables, wheat bran and whole grains.
Soluble fiber may help improve your cholesterol and blood sugar levels. It's found in oats, dried beans and some fruits, such as apples, oranges, strawberries and grapefruit.
The average American eats about 10 to 15 grams of fiber a day. However, the government's dietary guidelines recommend:
38 grams for men and 25 grams for women under the age of 5030 grams for men and 21 grams for women over the age of 50
The best way to boost your consumption of fiber is to eat a variety of whole grains, vegetables, legumes and fruits. When buying breads or grains, look for the word whole on the label. Try to eat breads with at least 3 grams of fiber per slice and cereals with 3 or more grams of fiber per serving. Try whole-wheat pasta, which has at least three times the amount of fiber as regular pasta.
Serving sizes: Keeping your food portions in check
Even if you're careful to eat a wide variety of foods, you may still be overlooking an important part of a healthy diet — serving sizes.
The size of your food portions affects how many nutrients and calories you're getting. And knowing how much food goes into a serving can help you gauge if you're eating too much of certain foods or not enough of others.
All in moderation
To practice moderation, avoid eating too much or too little from any one food group. By avoiding excessively large portions of certain foods, you're able to eat a wider variety of foods during a meal. Eating a variety of foods will ensure that you get all of the energy, protein, vitamins, minerals and fiber you need.
Try these suggestions for reducing food portions:
Serve food on plates instead of putting serving bowls on the table. Serve main dishes on a smaller plate. Ask for a take-home container when eating out. Save part of the meal for another time. Don't feel as though you have to clean your plate.
Publications for Download