"Balance, variety and moderation" used to be the mantra of good nutrition. But earlier this year, variety was quietly dropped from the mix in the latest version of the federal government's Dietary Guidelines for Americans. Why? Because a diet with a lot of variety -- the wrong kind, anyway -- can make you gain weight.
Blame your taste buds. They get bored quickly when you eat a particular food, a phenomenon called sensory specific satiety. Every bite after the first becomes a little less tasty. It's one reason why very monotonous diets can help you lose weight, at least until you get sick of them.
Add variety, and you're likely to eat more. A landmark English study showed that people ate about 15 percent more when three different shapes of pasta or flavors of cream cheese were served than when just one was offered.
"Also, people ate 60 percent more when served four different courses at a meal compared to four courses of the same food," says Barbara J. Rolls, Ph.D., Guthrie chair of nutrition at Penn State University and author of Volumetrics: Feel Full on Fewer Calories (HarperCollins, 2000). "Eating several different foods can help put on pounds."
But before you deliberately steer yourself into a nutritional rut, consider this: Some types of variety may help you lose weight. "Our research found that fatness was related to eating a wide variety of entrees and carbohydrate foods as well as sweets, snacks and condiments," says Megan A. McCrory, Ph.D., a researcher in the Energy Metabolism Laboratory at Tufts University's Human Nutrition Research Center on Aging in Boston. "But variety in vegetable choices was tied to leanness, and fruits and dairy foods had no association with either fatness or leanness."
So why was variety long promoted? "Before such a wide array of high-calorie, low-nutrient foods was available, variety was recommended as a way to make sure people got all the nutrients they needed," explains Adam Drewnowski, Ph.D., director of the nutritional sciences program at the University of Washington in Seattle. "In fact, we have an innate drive to eat a variety of different foods to stimulate our taste buds and improve our diet's nutritional quality." Finding that people were eating a variety of nutrition-poor, calorie-rich foods, the recommendation came under question. We know now that for both good health and weight control, your goal at each meal should be variety across healthful food groups rather than within them, with the exception of fruits and vegetables.
Analyze this meal
Which dinner contains the right kind of variety?
* Salad with regular dressing
* Chicken parmesan
* Pasta with tomato sauce
* Garlic bread
* Ice cream
* Minestrone soup
* Lamb or chicken kabob with tabbouleh salad
* Grilled mixed vegetables
* Sautéed broccoli
* Poached pears
Verdict: Meal 2 (Meal 1 contains too many carbohydrates, entrees and sweets and not enough fruits, vegetables and whole grains.)
Using variety for weight control
* Limit the number of high-fat, sugary and snack foods in your cupboards. "If you've stocked up on 10 different types of cookies, you will be more tempted to overeat by having some of each, rather than if you limit yourself to just one or two," says nutrition researcher Barbara J. Rolls, Ph.D.
* Eat a variety of vegetables, fruits and other foods that weigh a lot but don't have a lot of calories. They fill you up without piling on calories, and they're packed with nutrients.
* Follow the Food Guide Pyramid to get the right mix of foods across groups. For example, the milk group is unique in its abundance of calcium and the B vitamin riboflavin. Try for 6-11 servings of grain foods, 3-5 vegetable servings, 2-4 fruit servings, at least 2 servings of dairy products and 5-7 ounces or the equivalent from the protein group daily.
* Use fats like butter, margarine and oils sparingly.
* Monitor portion sizes. Weight gain results from eating too many calories, no matter where they come from. Restaurant portions tend to be too big for meat and pasta and too small for vegetables and fruits.
* Follow the new Dietary Guidelines (visit www.nal.usda.gov/fnic/dga/). They promote the right kind of variety.
To see if your diet contains the right kind of variety, check off each type of food you eat for three consecutive days. (Each can be checked only once.) If you check off at least 25 foods from all the USDA Food Guide Pyramid groups -- grains, vegetables, fruits, dairy, and meats and other protein foods -- chances are your diet has the right type of variety, says nutrition researcher Katherine Tucker, Ph.D., who developed the list. Checking off fewer than 15 foods means your diet could use more variety. Though there are no guidelines for variety within groups, common sense tells us that we should mix and match as much as possible. For example, don't eat just one type of fish and no other protein source or just pasta and no whole-grain products.
* Whole-grain breads
* Whole-grain cereals
* Nonwhole-grain breads
* Nonwhole-grain cereals
* Pancakes, muffins, biscuits
* Dark-green and leafy vegetables
* Deep-yellow and orange vegetables
* White potatoes and other root vegetables
* Tomato products
* Other vegetables
* Citrus fruits
* Other fruits
* Fruit juices
* Other dairy foods
Meats and other protein foods
* Liver and other organ meats
* Other meats
* Dried peas and beans
* Nuts and seeds
* Cookies, cake, desserts, chips, soft drinks, candy
* Margarine, butter and oils