A teacher who ate nothing but McDonald's for months lost more than 60 pounds.John Cisna, a science teacher from Iowa, saw the 2004 documentary "Super Size Me" and was curious to see if his health would deteriorate the way filmmaker Morgan Spurlock's did, he told local news station KCCI 8 back in January.Cisna has managed to keep off the weight months later. He just published a book called "My McDonald's Diet" about the experience."Eating McDonald's for breakfast, lunch, and dinner probably saved my life," Cisna says in his book, which offers daily meal plans for eating at the fast food chain.Here's a photo showing his progress.To jump-start his weight loss, Cisna started eating at the fast food chain for every meal and working on an amateur documentary with a team of students.Rather than ordering huge meals, he tried to adhere to a 2,000-calorie diet.When Cisna told the local McDonald's franchise about his plan, the restaurant said they'd give him meals free of charge.Here's what he'd eat on a typical day:Breakfast: Two Egg White Delights, a bowl of maple oatmeal and a bottle of 1% milk.Lunch: Salad.Dinner: A Value Meal with fries. Cisna said his favorite is the Big Mac.Cisna said his unconventional diet proves that fast food isn't evil."It's our choices that make us fat not McDonald's," he told the news station.But health experts argue that eating a McDonald's diet is a bad idea.Even if you lose weight, most fast food items lack nutrients necessary for a healthy diet.McDonalds Diet