From NPR.org, see link for source

There have been lots of talk about whether America’s obesity epidemic is due to an individual’s choice or if America’s food empires are increasing the struggle by making unhealthy food affordable and readily available. As a scientist, I’m a big fan of data and facts that can provide some suggestions about what may be the true cause.

The figure to the lift shows data on men of various body types (skinny, fit, heavy, and overweight) and how often they have had fast food in a three month period. With the current craze in America (blaming fast food as the source of obesity problems) you would expect that as you go from ‘skinny’ to ‘overweight’, you would expect that the percentage of consuming fast food would increase. This study does show that there is a correlation that as you go from ‘skinny’ to ‘overweight’ there is a vast increase in fast food consumption.

This data only shows a correlation; but it does not prove that this is due to fast food only. Most likely, multiple factors are involved (e.g., time spent exercising). The bottom line is, if you are focusing on improving your health, losing weight, etc., Consuming lots of fast food is a BAD IDEA. Why you say? Its because most fast food is high fat and low in nutrients. This means you can eat a ton of fast food; but soon after you will be hungry because your body still craves the nutrients that it needs. If you want to lose weight or lower your cholesterol, stay away from fast food as much as possible. For the original article, which this data came from, check the NPR article.