Need evidence? Data from the University of Toronto show that replacing 50 grams of carbs (about a muffin's worth) in your diet with 2.5 ounces of nuts each day helps control blood glucose in people with type 2 diabetes. Mice that ate a walnut-rich diet (the equivalent of 2 ounces daily in humans) were half as likely to develop breast cancer as those that didn't eat nuts, according to another study. And when researchers recently pooled the results of 25 clinical trials, they found that eating 2.4 ounces of any kind of nuts a day lowered " bad" LDL cholesterol by up to 7 percent and total cholesterol by up to 5 percent. Other studies have shown that people who eat several servings of nuts a week slash their cardiovascular risks by up to 74 percent, compared with those who eat nuts less than once a week.
If you're worried about nuts' high fat content, don't be. Women who consumed two or more nut servings per week had a slightly lower risk of obesity than those who ate nuts less frequently or not at all, the long-running Nurses' Health Study from the Harvard School of Public Health recently discovered.
"Nuts increase satiety," explains Joan Salge Blake, a registered dietitian and clinical associate professor in nutrition at Boston University. "That helps your meals go a little longer, so you don't snack as often."
Just don't eat too many. Stick to a daily serving — enough to fill only the palm of your hand.