I admit it—when the theory that friends can make friends fat came out a few years ago, I raised my eyebrows in disbelief. How could that be, I wondered—until I read Daniel Goleman’s SOCIAL INTELLIGENCE: THE NEW SCIENCE OF HUMAN RELATIONSHIPS, which explains how over time spent with someone, our brains tend to synchronize and mirror each other. Now I understand the need to hang out with healthy people, not merely because they raise our self-esteem and make us feel good, but because they may shape our lifestyle and habits. By the way, Goleman is also the author of EMOTIONAL INTELLIGENCE, a classic about our internal emotional world.

According to research, in part due to peer pressure and in part to how our brains adapt to and synchronize with one another’s, who you spend time with might encourage positive eating and exercise habits or put you in danger. Consider these questions. How do most of your friends relate to food and their bodies? Do they have a comfortable relationship with the scale or fuss about their weight and go from diet to diet? Are they “normal” eaters, for the most part, or do they pretend nutrition doesn’t matter, and live to eat? Does food have a pleasurable, reasonable place in their lives or do they talk a lot about it (what they’re eating or not eating) in way that absorbs most of their energy? When you’re with them, do you get caught up in their diet mentality or their you-only-live-once attitude toward food? Do they enjoy activities and moving their bodies or gripe about how they should exercise but fail to?

Moving farther afield, how do people you spend most of your time with value and take care of themselves? What are their relationships like with their partners, spouses, parents, children, friends, and coworkers? How do they feel about their jobs, whether taking care of the kids or being out in the work world? Are they basically optimistic, happy folks, or are they complainers and victims who rarely seem to find joy or meaning in anything? Is their life going somewhere or nowhere? Do they inspire you to become a better person and live up to your potential or hold you back, fearing your growth?

When you’re with people in your inner circle, pay attention to whether they have the values you are striving to live by, whether they’re working toward healthy goals or making excuses. Notice how you eat, think and behave around mentally healthy folks and how you eat, think, and behave around unhealthy ones. If you want to reach your eating and other goals, make sure your choices aren’t sabotaging them. The truth is, it’s as easy to hang around emotionally healthy people as unhealthy ones.