Unlike your car, your body doesn’t run equally well whether it’s completely topped off or just a drop away from empty. So it’s critical to keep your fuel level relatively even throughout the day — eating too much at one meal or not enough at another can leave you lagging. That’s one reason nutrition experts are virtually unanimous in their advice to eat small meals — as many as six — throughout the day. “If you refuel every few hours, you avoid the boom and bust cycle that makes you feel depleted and can also lead to overeating,” says Sari Greaves, RD, a New York City-based spokeswoman for the American Dietetic Association. If you rely on caffeine and sugar to keep you going at various times of day, you’re not fooling your body. “There’s no denying the quick fix you get from both, but the effects don’t last long,” says Greaves. She recommends sticking with “foods that take the edge off and prevent rebound hunger.” That means meals that contain both complex carbohydrates and lean protein.
Count on Carbohydrates
Carbohydrates have gotten a bad rap thanks to the last decade’s worth of fad diets, but they are actually the body’s main source of fuel. It’s just that in our culture, we rely too much on the carbohydrates that are found in sweet and processed foods, rather than on the complex ones found in whole grains, fruits, vegetables and beans. It’s the complex carbs that make you feel comfortably full for longer (which is why they are helpful for weight loss too), according to Cindy Moore, MS, RD, director of the Nutrition Therapy Department at the Cleveland Clinic. “Whole grains, including whole-wheat bread or whole-grain pasta, have staying power because you digest them more slowly than refined grains,” she says, “and they also keep blood sugar levels stabilized so you don’t feel like your batteries are running low.”
About 60 to 65 percent of your total daily calories should come from carbohydrates, ideally of the complex variety. One reason to limit refined carbohydrates (e.g., white and enriched flour and white rice) is that, because their fiber has been stripped away, you use the energy they provide quickly and get hungry again sooner than you do when you eat the more fibrous complex carbs.
Along with the complex carbs, you need protein. “The cells in our body are constantly turning over and need to be replaced,” says Moore. “Protein is necessary to help fuel the building of new cells.” Protein also helps regulate body processes, such as keeping blood vessels open, and it supplies energy if you aren’t eating enough carbohydrates. A typical adult needs between 0.6 and 0.8 grams of protein per 2.2 pounds of body weight. If you weigh 140 pounds, that means you need about 44 grams a day; if you weigh 200 pounds, you need about 63 grams a day. A serving of chicken or beef — which is approximately the size of a deck of cards — contains roughly 21 grams of protein. A cup of yogurt contains approximately 11 grams, and an egg contains about seven.
What else does your body need? Iron is a mineral that we literally can’t live without. Iron’s main job is to carry oxygen in the hemoglobin of red blood cells. In turn, the hemoglobin takes oxygen to all the cells in your body. That’s why if you’re not getting enough iron, you feel weak and fatigued. While Popeye may have gotten his iron from spinach, these days it’s easy to find it in fortified cereals and breads, says Moore. Iron from animal sources (called heme iron) is better absorbed by the body than iron from plant sources (nonheme iron). The best sources of heme iron include beef liver (although it’s also very high in cholesterol), lean sirloin, lean (as in 90 percent fat free) ground beef and skinless chicken. Nonheme sources include fortified breakfast cereals, pumpkin seeds, soybean nuts, leafy greens such as kale, prune juice and bran; many varieties of beans are also good sources of iron. How much is enough? Men 19 years and older need 8 mg of iron a day; women who are not pregnant and are between 19 and 50 need 18 mg a day (during pregnancy, they need 27 mg a day). After age 50, 8 mg is adequate for women too. If your iron levels are low, try eating meals that include both iron and vitamin C to maximize iron absorption.
Now hear this: Fat is not a four-letter word! Yes, a high-fat diet — especially one that includes mainly saturated fats (e.g., meat, whole-milk dairy products, butter) — is unhealthy and causes all sorts of health havoc, from heart disease and obesity to some types of cancer and diabetes. But we actually need some fat in our diet to stay healthy. Like carbohydrates and proteins, fat supplies energy that powers both mental and physical activity. And without it we can’t make two essential fatty acids, linoleic acid and alpha-linolenic acid, which we need to help keep our main motor — our brain — running.
The best sources for the fats we need are fish (salmon, anchovies and sardines are especially good) and oils such as olive, canola, sunflower and safflower. The recommended daily limit for fat, according to the American Dietetic Association, is 30 percent of our daily calories. Of that total, at least 20 percent should come from “healthy” fats and no more than 10 percent from saturated fat.
How Much Is Enough?
The American Dietetic Association has a formula that can help you figure out just how much energy you need, in the form of calories, to maintain (or reach) a healthy weight.
1: Multiply your healthy (or ideal) weight in pounds by 10. For example, if you weigh 160 pounds, your basic energy need is 1,600 calories.
2: Now figure out your how much more fuel you need for physical activity. If you are sedentary, multiply your basic energy need by 20 percent; if you engage in light activity (housework, walking leisurely), multiply by 30 percent; if you engage in moderate activity every day (brisk walking, very little sitting), multiply by 40 percent and if you are very active, multiply by 50 percent. For example, if you are moderately active, 1,600 x 0.30 = 480 calories, plus 1,600, for a total of 2,080 calories.
3: Next, figure out how much energy it takes for digestion and absorbing nutrients by multiplying by 10 percent: 2,080 x 0.10 = 208 calories.
4: Finally, add the total number of calories together for your total energy needs. In this case, it’s 2,288 calories a day.