In a nutshell: a handful a day keeps you slim and healthy. (food).(Illustration)

Mollie Katzen, the best-selling vegetarian cookbook author, known for the Moosewood Cookbook and Mollie Katzen's Sunlight Cafe, is no longer a strict vegetarian. Although Katzen now enjoys fish and poultry--and even red meat occasionally--she still gets much of her protein from non-meat sources.

"I go for nutritionally dense bites," she explains, "so I reach for nuts rather than a sandwich. Instead of toast, I have a handful of them at breakfast with an apple and a small piece of cheese."

Remarkably trim and full of energy, Katzen is one of a growing crowd of smart eaters who is enthusiastic about, nuts. This interest is fueled by studies showing that eating one to two ounces of nuts a day cans actually help you lose weight and keep it off while reducing the risk of heart disease, diabetes and high blood pressure. Since nuts are high in fat and calories, how can this be?

fat facts

Fat makes you feel full. It also suppresses hunger so you don't eat as frequently, as Richard Mattes, PhD, RD, Professor of Medicine and Nutrition at Purdue University, witnessed in studies he conducted. In one six-month study, people were given a bag of nuts and told to eat as much as they wanted every day. They experienced no weight gain because, feeling satisfied, they spontaneously cut back on other foods. Next, the study's volunteers were required to eat 500 calories worth of nuts per day while cutting back on other foods to keep total calories constant. And, again, they felt satisfied. Finally, when subjects were required to eat the nuts plus their usual calories, they simply could not do it. So the study had to be terminated. Remarkably, during this final phase, people gained less weight than expected because, as earlier, they had reduced their intake of other foods since the nuts kept their hunger satisfied.

The unsaturated fats in nuts are actually essential for our health. Eating the right kinds of fats--which also include olive oil rich in monounsaturates and canola oil rich in polyunsaturates--reduces blood cholesterol and improves the ratio of high-density lipoprotein (HDL), the "good" cholesterol, to low-density lipo-protein (LDL), the "bad" cholesterol. This helps explain why, in countries where people still eat the traditional Mediterranean diet, there's a lower incidence of heart disease. Even though up to 40 percent of the calories consumed in this diet come from fat, the fat is mainly derived from healthier sources such as nuts, olive oil and fish rather than from dairy and other animal foods.

heart health