People often lose weight as they get into their 70s and 80s, and it's often due to chronic disease, ... A third to a half of people in the older age groups have at least one chronic disease like heart disease, stroke, congestive heart failure, or cancer.
The effect of cigarettes on the risk of disease is so powerful and it's so difficult to control for factors like the intensity and duration of smoking that the only way to eliminate the bias is to look at people who have never smoked,
These results do not suggest that people have carte blanche to eat fatty foods without health problems.