Just goes to show it's not where you eat, it's what you put in your mouth:

Inspired by the documentary "Super Size Me," Merab Morgan decided to give a fast-food-only diet a try. The construction worker and mother of two ate only at McDonald's for 90 days and dropped 37 pounds in the process.

It was a vastly different outcome than what happened in the documentary to filmmaker Morgan Spurlock, who put on 30 pounds and saw his health deteriorate after 5,000 calories a day of nothing but McDonald's food.

I always thought Spurlock's idea was clever, but not particuarly scientific or even conclusive. If you could eat 5,000 calories of tofu, lettuce, and brussel sprouts a day I'm quite sure there would be equally significant health issues.