A hamburger or a salad? A baked potato or French fries? A milkshake or orange juice? A candy bar or an apple? We have to make choices about what we eat every day.
New food guidelines and the food pyramid that goes with them emphasize that we should eat more fruits, more vegetables, and more whole grains than we typically do now. We should also avoid lots of sugar, salt, and certain types of fats. And we should get plenty of exercise.




The best way to stay healthy is to eat foods packed with nutrients.

USDA



As a young person, you might not think that these recommendations apply to you. After all, you might consume greasy pizza and sugared soda pop every day and feel just fine. Or perhaps you stay skinny no matter how many French fries and candy bars you eat.

There are plenty of reasons to swallow your pride instead of a milkshake and pay attention to the guidelines, says Joan Lyon. She's a nutritionist at the United States Department of Agriculture (USDA) in Alexandria, Va.

Evidence continues to build that eating certain kinds of foods protects people from cancer, heart disease, obesity, diabetes, weak bones, and other health problems. Eating the wrong kinds of foods, on the other hand, causes your body harm.

As a dietician in the U.S. Army for 21 years, Lyon worked with a lot of young soldiers. They didn't think it mattered what they ate, she says. They felt like they were going to live forever.

But, if you don't pay attention to what you eat when you're young, Lyon says, it's really, really hard when you're old and you find yourself sick and unable to do much about it.

New information

Every 5 years, the U.S. government enlists scientists to update a document called "Dietary Guidelines for Americans" and a food pyramid illustration that goes with it. (See "Building a Food Pyramid.") As scientists learn more about the human body, nutrition, and disease, they adjust the guidelines to reflect the new information.




The cover of the latest edition of "Dietary Guidelines for Americans."

USDA



Lyon was a member of a large staff that helped a team of 13 scientists put together the latest set of guidelines. The USDA and the Department of Health and Human Services released the guidelines in January.

Coming up with new guidelines every 5 years is a complicated process. More than a year before the new report is due, experts gather the latest scientific evidence on vitamins, minerals, and various foods. They discuss the findings. Sometimes, different studies seem to give opposite results. Sometimes, the evidence is incomplete.

"It's a very long process," Lyon says. "People can interpret science in different ways even when they're looking at the same data." It's sometimes tough to come up with firm conclusions that everyone agrees with.

And new discoveries keep coming along. A team of researchers in England and Denmark, for example, recently discovered a compound in carrots that appears to reduce a rat's chances of developing cancer.

This kind of study wouldn't have carried much weight with the USDA committee, though, because the scientists prefer to look at studies involving people. If researchers were to repeat the rat experiment with people and got similar results, the 2010 guidelines might end up suggesting that we eat more carrots.

Weight control

More than the old guidelines, the 2005 recommendations focus on weight control, Lyon says. (See "Packing Fat.")

"There's an energy equation," she says. "The calories you take in need to balance the amount of energy you expend in terms of physical activity and exercise, or you'll end up gaining weight. You need to make your calories work for you."




Getting plenty of exercise is an important part of controlling your weight.

USDA



The best way to stay healthy, Lyon says, is to eat foods that are packed full of nutrients.

Instead of the five servings of fruits and vegetables that used to be recommended, the new guidelines suggest that adults eat even more than that: 2 cups of fruit and 2 1/2 cups of vegetables each day.

Kids should adjust the amounts of fruits and vegetables based on energy needs and size. It might be worth talking to your doctor or school nurse for advice on the amounts that are best for you.





The widths of the colored triangles in the new food pyramid show roughly how much of different food groups a person should eat: Grains (orange), vegetables (green), fruits (red), oils (yellow), milk (blue), and meat and beans (violet). The new pyramid also emphasizes the need for exercise and the steps that a person can take every day to improve his or her diet and lifestyle.

USDA