LONDON - If it really is what's on the inside that counts, then a lot of thin people might be in trouble.
Some doctors now think that the internal fat surrounding vital organs like the heart, liver or pancreas — invisible to the naked eye — could be as dangerous as the more obvious external fat that bulges underneath the skin.
"Being thin doesn't automatically mean you're not fat," said Dr. Jimmy Bell, a professor of molecular imaging at Imperial College, London. Since 1994, Bell and his team have scanned nearly 800 people with MRI machines to create "fat maps" showing where people store fat.
According to the data, people who maintain their weight through diet rather than exercise are likely to have major deposits of internal fat, even if they are otherwise slim. "The whole concept of being fat needs to be redefined," said Bell, whose research is funded by Britain's Medical Research Council.
Without a clear warning signal — like a rounder middle — doctors worry that thin people may be lulled into falsely assuming that because they're not overweight, they're healthy.