[steelrat1 (OP)]

why don't we study people that never get ill?
is it chance or genetics?

[grizelda]

They probably caught a lot of diseases when thy were children. If they didn't die from them, their immune systems would have acquired methods to protect them from future recurrences.

[RD]

http://www.okicent.org/study.html

[chris]

That's a very good question and, in fact, one scientist we interviewed on the podcast a few years ago, Professor Steve O'Rahilly who works on obesity and diabetes at Cambridge University, said much the same. His point was that becoming fat in the present world environment is an inevitably and therefore studying the average fat person to understand obesity is not the way to find the answer. Instead, he said, we should be looking at the "normal" people who don't get fat, because clearly they have the ability to remain at the normal weight despite the obesogenic influence of their environment; genetically, therefore, they may have more to tell us about the mechanisms of weight gain and how to reverse or prevent it.

Chris