Thin people can put themselves first.

For five years, Anne Fletcher, a registered dietitian and the author of Thin for Life (Houghton Mifflin, $15, www.amazon.com), worked in an obesity clinic. “So often the women I saw were people who refused to take time for themselves,” she recalls. “Their whole lives were spent giving, giving, giving — which women tend to do anyway, but it was really to a fault. Sometimes you need to put yourself first.”

Thin women prioritize eating right, exercising regularly, and reducing stress — all of which are conducive to staying slim. Fletcher confesses to missing the occasional Little League game to work out but contends that such behavior shouldn’t induce guilt. Rather, it’s about taking care of yourself.

“When people take the reins, they realize that the solution to weight control is inside them, not in some magic potion or fad diet that their mother or sister is on.”