SHEEP DO IT. Horses do it. Cows do it.

And, say nutritionists, it is becoming the pattern for more and more people.They call it "grazing" - or snacking on minimeals throughout the day.

"Since everyone is always rushing around in a hurry these days, there's often no time for three square meals," says Marilyn Stephenson, assistant to the director of the Food and Drug Administration's Office of Nutrition and Food Science.

Grazing is a way of filling in those necessary calories and nutrients you might otherwise miss due to incomplete or skipped meals, says FDA writer Cheryl Platzman Weinstock. And done wisely, grazing is not only good for you, it can be fun.

How you graze and what you choose to graze on should depend on your age and your lifestyle. Adults, for example, must be more careful than children about snacking. Children, teens and elders are most likely to benefit from grazing.

The idea is to make sure that your snacking is a part of your day's total nutrition intake. Keep calories in mind and make sure that your grazing is well-planned to include essential nutrients.

Use the "calorie-salary" rule, advises Weinstock. "Determine your daily `salary' of calories and make sure you `spend' no more than that over the course of your meals and snacks for the day."

For example, if you know you'll be eating lots of foods at a party, eat low-calorie foods the rest of the day. If you find yourself eating more calories than usual in a day, increase your physical activity.

Choose snacks that offer more than "empty calories" with few nutrients. A few sweets can be acceptable if nutrient needs are met from other foods and if you can afford the extra calories from a weight standpoint. If you crave sweets, try some portion control - a bite-sized candy bar or half a Popsicle.

"If you get nutrition-wise and develop nutrition literacy," says Stephenson, "snacking will work for you."