(CNN) -- Twinkies. Nutty bars. Powdered donuts. For 10 weeks, Mark Haub, a professor of human nutrition at Kansas State University, ate one of these sugary cakelets every three hours, instead of meals. To add variety in his steady stream of Hostess and Little Debbie snacks, Haub munched on Doritos chips, sugary cereals and Oreos, too. His premise: That in weight loss, pure calorie counting is what matters most -- not the nutritional value of the food. The premise held up: On his "convenience store diet," he shed 27 pounds in two months. For a class project, Haub limited himself...