Discretionary calories.

Those two words are likely to become part of the nutritional lexicon when new U.S. Dietary Guidelines are unveiled early next year. The guidelines, updated every five years, provide a nutritional blueprint for the nation.

So what are discretionary calories?

They're the equivalent of a little loose change in your pocket -- the difference between the calories needed to provide all the essential nutrients for health and the calories burned daily. They're not just the icing on the cake, they're the cake and the icing. They're also the cream in whole milk, the added sugar in a soft drink and the fat in fried food. In other words, they're the high-calorie foods that may appeal to your taste buds but carry minimal nutritional benefits and aren't so great for your waistline.

And we eat far too many of them.

Here's how it shakes down: A typical 40-year-old sedentary man who burns about 2,350 calories per day needs 1,938 calories to meet his basic nutritional needs. The difference -- 412 -- is the number of discretionary calories that he has left. He could use them, for example, to drink a beer and eat a small bag of potato chips.

Doing that will keep his weight stable. But if he goes overboard day after day, as too many Americans do, there's a problem: weight gain.

It's learning to balance energy consumption with physical exertion -- something that will sound familiar to Lean Plate Club members -- that can help more people achieve a healthy weight, the committee said.

Here's a taste of what else committee members -- 13 experts in nutrition and physical activity -- chewed over in writing their report, which is slated for delivery this month to the U.S. Department of Health and Human Services and the U.S. Department of Agriculture.

Calories count. In fact, the idea of finding your own daily caloric balance -- how much you eat vs. how much you burn with physical activity -- is likely to be a mainstay of the upcoming guidelines. The data suggest that "most people need to improve the quality of their diets and . . . need to reduce their calorie intake somewhat," the scientists noted in their draft report. "They need to choose meals and snacks that are high in nutrients, but low to moderate" in calories.

Move it! To maintain good health, aim for at least 30 minutes of moderate activity -- brisk walking, for example, at 3 to 4 mph -- on most days. Adults trying to shed a few pounds or maintain weight loss may need to boost that to 60 to 90 minutes of movement. Children also need at least 60 minutes on most days. Also beneficial: weight training to boost muscle strength and endurance and increase lean body mass. And where possible, limit sedentary living -- television watching, computer use -- during leisure time.

Reach first for the fruit and veggies. Most Americans still fall short on these important foods, filled with fiber, complex carbohydrates, essential minerals and vitamins and a host of health-promoting phytonutrients. The committee's advice: Reach for five to 13 servings (2.5 to 7.5 cups) of fruit and vegetables daily. (The low number is enough for children; large men and teens should shoot for the high end of the scale.) Start by increasing dark green vegetables such as spinach and bright orange vegetables such as carrots, sweet potatoes and pumpkin -- lacking in too many diets, said the committee.

Carbs are fine. Just make them whole grains. The committee said it's important to eat at least three servings of whole grains -- equal to about a slice of whole wheat bread, three-quarters of a cup of whole grain cereal and a half-cup of wild rice -- per day. In fact, the committee noted that an optimal daily food intake to maintain long-term weight loss contains 45 to 65 percent of daily calories from carbohydrates, including fruit and vegetables, 20 to 35 percent from fat; and 10 to 35 percent from protein. Also, the committee noted that "both low-carbohydrate and low-fat diets limit the variety of foods that can be eaten and therefore may be difficult to follow long-term."

Easy on the salty fare. Many people consume "too much salt, much of it from processed foods," the committee's draft report notes -- echoing previous findings from the National Academy of Sciences. Evidence suggests it's best to aim for fewer than 2,300 milligrams of sodium per day -- roughly the amount found in about three slices of pepperoni pizza.

Have some "moo juice." Low-fat and nonfat milk is another food that the experts said is often under-consumed by Americans. They recommended three cups of milk per day for those who eat 1,600 calories or more; two cups per day for those consuming less. Those who are lactose-intolerant can reach for yogurt or reduced-lactose milk, the committee said.

Eat healthy fats. They are part of a healthy diet, the committee noted, and provide the essential vitamins, A, D, E and K, plus carotenoids, which are converted in the body to vitamin A. Among the good choices mentioned by the committee: soybean, corn and canola oils, which provides essential fatty acids. Those and other oils, including olive oil, can also help control damaging low-density lipoprotein, the committee said. But keep saturated fat -- such as that found in butter -- to less than 10 percent of total calories and trans fat to less than 1 percent of total calories. And dietary cholesterol? Limit it to 300 milligrams per day or less -- about the amount found in one egg yolk, the committee said.

Monitor your weight. Stepping on the bathroom scale is important for weight maintenance, since "individuals have no practical way . . . to know if they have a calorie deficit or excess in a day," the committee noted. Think of it like monitoring your bank account or 401(k): It helps to know the bottom line from time to time.

Imbibe alcohol sparingly. Potential health benefits come only from light to moderate consumption of alcohol -- one drink per day at most for women; two drinks per day for men. (A drink is 12 ounces of beer, 1.5 ounces of distilled spirits or five ounces of wine.) The committee also noted that any potential health benefits apply only to women 55 and older, to men 45 and older and to those at increased risk of heart disease.

Share Your Tips or ask questions about healthy nutrition and activity when Sally Squires hosts the Lean Plate Club online chat, from 1 p.m. to 2 p.m. today, on www.washingtonpost.com. Can't join live? E-mail leanplateclub@washpost.com anytime.

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