The researchers at the Cornell University Food and Brand Lab maintain a list of people who have done something fairly unusual in today’s world: They’ve been a healthy weight for their entire lives, never fluctuating more than five or 10 pounds, barring pregnancy.

The purpose of the Global Healthy Weight Registry, essentially, is to share the secrets of not getting fat with the rest of us. It’s just another way that scientists are trying, mostly in vain, to help curb the obesity epidemic.

The Food and Brand Lab recently released another ream of data from the 147 registry participants. Some of their answers are just as frustratingly practical and responsible as you’d expect: Half weighed themselves at least weekly, all but 4 percent eat breakfast, and all but 10 percent of them exercise. Forty-two percent work out five or more times per week. The majority always eat vegetables at dinner and say chicken is their “favorite meat.”

But here’s the surprising thing: Nearly half—48 percent—said they don’t diet. Three-quarters of them “rarely” diet. These people are thin, and have been thin their entire lives, yet they have never so much as perused the Jenny Craig website.

One explanation could be good genes. The healthy-weight registrants might never diet because, being naturally thin, they never need to. Still, that wouldn’t explain why they do all those other things—the exercising, the salad lunches, all that poultry. Clearly, they are putting some effort into their figures.