(NEWSER) – Want to lose some weight? Try eating nothing but McDonald's for 90 days. That's what science teacher John Cisna did, and he not only lost 37 pounds but also saw dramatic improvements in health markers like cholesterol. The Iowa man was inspired to try his experiment after watching Supersize Me, the documentary in which eating McDonald's for a month led Morgan Spurlock to weight gain and worse health. But in Cisna's case, he kept to strict limitations: 2,000 calories per day, while sticking close to the recommended dietary allowances for fat, cholesterol, and nutrients.