Mayo Clinic Radio: Healthy Food Choices When it comes to dieting, the focus often has been on eating fewer calories as the key to losing weight. But a new study, published recently in JAMA, found that what you are eating is an important factor in weight loss. The study found that people who cut back on added sugar, refined grains and highly processed foods, while concentrating on eating plenty of vegetables and whole foods — without worrying about counting calories or limiting portion sizes — lost significant amounts of weight over the course of a year. Researchers hope that a focus on quality versus quantity when it comes to calories may be a way to combat the obesity epidemic in America.