UNC-Chapel Hill researchers have a pretty comprehensive study  out today that looks at how – and not just what – people eat over the last thirty years. The results point to what they think is a major cause of people getting much, much heavier: people are eating significantly more in bigger portions at each meal and they are eating more often between meals.
This research goes way beyond the “supersize me” fast food debacle, because it looks at what people are eating in a wide variety of situations over a long period of time. I’ve read the full article and I think the authors are pretty persuasive that, at least based on this study, a primary problem causing our obesity epidemic is simply that people are eating way too much.
Just like anything in public health, it’s always hard to separate out the causes with obesity. With cities and towns set up for cars and not pedestrians or bicycles, with huge increases in soda consumption coupled with corresponding large drops in average price for sugary drinks, with the elimination of gym and recess as part of the school day in many areas, there are plenty of potential causes.
However, this UNC study on portion size is persuasive in its arguments mainly because it looked at so many people over such a long period of time for some pretty specific behavior. It’s worth a look.