Most everyone knows it's the surest way to lose weight and keep it off.
But the rate at which waistlines are expanding in the United States — land of supersized fast-food meals and endless television options for the couch-potato set — suggests that too many people haven't taken to heart the message to stop stuffin' it and start huffin' it.
Experts say consumers aren't entirely to blame.
Studies touting the health benefits of certain foods one week seem to be contradicted by follow-up research. And dietary guidance from years past is being revised. Eggs, for example, are back in favor, years after being shunned over concerns about cholesterol.
It's a recipe for confusion — not the ideal diet.
"People are getting messages from the left and right, often about just the latest findings from a new study, and that's not usually sufficiently reliable," said Dr. Walter Willett, chairman of the nutrition department at Harvard School of Public Health.
"That can make what is even at best a complicated story really very confusing," he said.
At this time of year, the desire to lose weight often becomes more pressing, with summer a few weeks away and the latest in skin-revealing fashions beckoning from store displays.
But whatever the season, conflicting food advice leads many people to give up and resolve to "eat what I want," added Sheah Rarback of the American Dietetic Association.
Willett also blames the Food Guide Pyramid, created by the government to encourage healthier eating. Foods that should form the base of the diet, mostly grains, are represented in the pyramid's wide bottom; foods to be eaten sparingly — fats, oils and sweets — are in the tip. Fruits and vegetables, dairy products and meats, fish and poultry are in the middle.
Willett said the food pyramid implies that all fats are bad when there are some good ones, like those in fish. That mistaken message, in turn, led many people to lose sight of the fact that, when it comes to losing weight, calories are what really count; 3,500 of them equal about a pound.
So, as they filled up on fat-free cookies, ice cream and other morsels produced by the food industry, the calories — and the pounds — piled on.
Willett has assembled an "ideal" diet of his own that relies on healthier plant oils instead of animal fats, and whole grains and high-fiber carbohydrates (think brown rice and wheat pasta) over refined grains like white rice.
It emphasizes plenty of vegetables and fruits, and healthy protein sources — such as fish, poultry, nuts and legumes — instead of red meat and high-fat dairy products. Willett also recommends a daily multivitamin, moderate alcohol consumption and regular physical activity.
Some recent studies suggest this as an "ideal" meal: a slice of fish (the oilier, the better) cooked in garlic, shallots, onions and tomatoes, served with broccoli and washed down with beer, wine or a mixed alcoholic drink. Finish with fresh fruit and a steaming cup of tea.
It's very different from the stick-to-your-ribs, meat-and-potatoes diet of not so long ago. But recent scientific studies have found that:
- Eating even moderate amounts of oily fish, such as mackerel, salmon and sardines, may cut by half the risk of prostate cancer.
- Men in China have the world's lowest rate of prostate cancer and one of the reasons may be a diet rich in garlic, shallots and onions.
- A diet rich in tomato sauce, ketchup and other tomato-based products that contain lycopene also can lower the risk of prostate cancer.
- Broccoli and broccoli sprouts contain a chemical that kills the bacteria responsible for most stomach cancers; broccoli also has been shown to reduce prostate cancer.
- As little as half an alcoholic drink a day can reduce the risk of heart attacks, regardless of whether the chosen beverage is beer, red or white wine or hard liquor.
- Edible cranberry-like berries from the autumn olive plant have been found to have up to 18 times more lycopene than tomatoes, and could also be a cancer fighter.
- Longtime tea drinking may make bones stronger, and reduce the risk of dying after a heart attack.
All things in moderation, in other words.
Even the smallest changes matter. Eating one tablespoon less fat per day will lead to a 10-pound weight loss in a year, said Katherine Tallmadge of the American Dietetic Association.
"It's not about trying to make sweeping overhauls that are doomed to fail," she said.
Government efforts to encourage good eating date back to the 1890s, when the Agriculture Department prepared the first food tables listing data on the protein, fat, carbohydrate, ash and "fuel" value for some commonly available foods.
Food groups didn't appear until 1916, when five were created: milk and meat, cereals, vegetables and fruits, fats and fat foods, and sugars and sugary foods.
The "Basic Seven" food groups came along during World War II, with suggested alternatives in case the war limited supplies. About a decade later, the guide was scaled back to the "Basic Four" — milk, meat, bread and cereal, and vegetable-fruit groups.
The current "Food Guide Pyramid" came along in 1980, with six groups.
There is also the "5 A Day" slogan designed to remind people to eat at least five servings a day of fruits and vegetables. Late last year, government health advisers upped their recommendation for physical activity to at least one hour a day, from 30 minutes.
But despite all this guidance, the nation is getting fatter and wider.
Nearly two-thirds, or 64.5 percent, of U.S. adults are overweight, compared with 56 percent in 1994, federal statistics show.
By Darlene Superville
By Darlene Superville