The influencer: Your svelte friend
People tend to eat 1.5 times more in the company of a thin person who eats a lot than an overweight one, reports a study out of the University of British Columbia.
The influencer: Your date
Women consume 100 fewer calories when dining with a male date than with a female companion, according to research from McMaster University in Ontario.
The influencer: Your glass-half-full pal
Researchers from Doshisha University in Kyoto, Japan, theorize that optimists are more likely to give in to temptation: They may nudge you to "live a little," too.
The influencer: Your husband
Married women are more than twice as likely to be obese as those who are single or dating, reports a University of North Carolina at Chapel Hill study.
The influencer: Your friend's friends
Research from Harvard Medical School suggests that your risk of becoming obese increases 20 percent if a friend of a friend is also obese.
Next: The truth about fat cells