Proving a point to his students, an Iowa high school teacher shows you can lose weight with fast food, eating only McDonald’s menu items for three months.

High school teacher loses weight eating only at McDonald’sThe teacher worked with his students to create diet requirements over a 90-day period. According to the USA Today, the diet included strict allowances for protein, carbohydrates and cholesterol, and was limited to less than 2,000 calories per day.

Eating every meal at the burger chain, John Cisna, a high school teacher in the Colo-Nesco School District in Colo, Iowa, chowed down on Big Macs, ice cream and Value Meals, but also selected lighter items like salads and oatmeal.

Cisna’s point was to show what you eat is more important than where you eat. It worked, he lost 37 pounds by the end of the program.

Part of the 90-day challenge included exercise. Cisna walked for 45 minutes every day. He was able to reduce his cholesterol by 79 points to 170 by the end of the three months.

Although McDonald’s isn’t copying Subway’s campaign with Jared, the famous spokesman who lost 245 pounds with help from the deli chain, they were pleased with the teacher’s results.

"We congratulate John Cisna on his weight loss and improved overall health, and we are pleased he was able to accomplish his goals by making balanced choices, which included many of his favorite McDonald's menu items," says Cindy Goody, senior director of nutrition at McDonald's USA, in a statement.