Surround Yourself with Active People
Research supports the idea, too—that obesity is "contagious" and that when we eat with other people, their food choices affect us—how much we eat, what we eat, and how we feel about it. We are always making decisions based on other people's thoughts, actions and habits, which is why it's so important to surround yourself with people whose values and habits support your healthy lifestyle.
I believe that habits are contagious. If your friend is always negative or feeling down, it's hard not to feel the same way yourself. If your family lives to eat, you might have a hard time saying no to certain foods, too. And if your friends are always getting on and off the weight-loss or exercise rollercoaster, then you might not always have the support you need to get to the gym on a regular basis.
But the inverse is also true. Surround yourself with fit, active people who enjoy healthy foods and living healthy, and you'll be more likely to make the same healthy choices.