Eating good-for-you foods when you get together with friends can be contagious, so lead the way. American researchers who analyzed the social ties of more than 12,000 people who participated in a major heart study found clusters of thin people and obese people, which suggests that friends have a strong influence on weight. That’s something Diane Finegood, scientific director of the Institute of Nutrition, Metabolism and Diabetes in Burnaby, B.C., part of the Canadian Institutes of Health Research, has seen first-hand. “If I’m at a buffet, I’ll take a dessert plate, which is smaller than a dinner plate, and use that for my meal,” she says. “People I’m eating with see that, and it’s an opening for talking about choices, and it gets others on board.”