Slow food is all the rage, but here is a bit more evidence that you will be skinnier for it. Catherine Rampell plotted recent OECD data on obesity rates against the time spent eating per day. The French, who know how to eat, spend a lot of time at it and yet are pretty svelte. However, as a Canadian, I think the data are suspicious. We eat pretty much the same diet at the same speed as Americans, with half the obesity rate. As they say on XKCD, correlation does not imply causation.
After all, other studies have linked lack of sleep to obesity, yet it is clear that both the French and Americans sleep a lot, and Koreans and Japanese don't.