Thinfluence: Thin-flu-ence (noun) the powerful and surprising effect friends, family, work, and environment have on weight

Tackling a weight problem is often viewed as a personal responsibility that requires making healthier choices. The latest research, however, shows that external factors—from family and friendships to advertising and the workplace environment—make an equal, if not greater, contribution. Just look at the stats: A person's chance of becoming obese increases by 57 percent if a close friend is obese, 40 percent if a sibling is obese, and 37 percent if a spouse is obese.

That's where Thinfluence c...