You may not need a gastric bypass or lap band surgery to lose weight – IF you have a close friend or family member who had the surgery themselves. Because a new study has found that after someone has weight-loss surgery, the people in their close social circle are more likely to lose weight, even without surgery!

Researchers at Stanford University recorded the weight of gastric bypass patients and their family members right before the surgery. They also completed questionnaires about their lifestyle. Like, “How much alcohol do you drink?” And “How much TV do you watch?”

One year later, they weighed the patients and their families again. And gave them another lifestyle questionnaire to fill out.

The result? Every family member got healthier after the gastric bypass surgery. Not only did the patients keep the weight off, but the average adult family member lost 8 pounds, and their waistline shrank 3 inches.

Lead researcher Dr. John Morton says that healthy habits rub off. After a gastric bypass surgery, patients have to adopt a super-strict eating and exercise regimen to keep the weight off for good. And, family members can’t help but copy the behavior of their loved one. After all, would you crack open a bag of cheesepuffs if the person sitting next to you was snacking on walnuts?

In fact, family members drastically cut down on bad habits, like emotional eating and drinking alcohol. And instead picked up healthy ones, like eating a balanced diet, and exercising every day.