Back in 2004, Morgan Spurlock directed and starred in a documentary called Super Size Me in which he ate nothing but McDonald's food for 30 days to prove how unhealthy such a practice would be.

At the end of month, Spurlock had gained more than 24 pounds and was in worse health than when he had started.

I saw the documentary and came away thinking it was an interesting thing for him to do but that there was a flaw in his experiment. Spurlock had consumed only the highest-calorie items on the menu. He had only drunk regular sodas--no sugar-free, no unsweetened iced tea. And he drank only the large 32-ounce beverages.

Anyone would gain weight "dieting" like that for a month. He never ate any of the salads or  grilled chicken. He never opted to have condiments like mayonnaise removed from his sandwiches.

Essentially, he wasn't proving that you can't help but gain weight only eating at McDonald's. He was proving that you can't help but gain weight only eating CERTAIN FOODS at McDonald's. So I felt he was being a little disingenuous.

Enter science teacher John Cisna of Iowa. He went on a 3-month McDonald's diet, threw in a 45-minute walk every day, dropped 37 pounds. He ate things like egg white delights and oatmeal for breakfast and salads for lunch. He even tossed in Big Macs and sundaes for dinners.

Yep, nothing but McDonald's for 3 months. Now THERE'S a documentary I want to see.