ROCHESTER, Minn. — New research from Mayo Clinic shows that lack of sufficient sleep combined with free access to food increases calorie consumption and consequently fat accumulation, especially unhealthy fat inside the belly. Findings from a randomized controlled crossover study led by Naima Covassin, Ph.D., a cardiovascular medicine researcher at Mayo Clinic, show that lack of sufficient sleep led to a 9% increase in total abdominal fat area and an 11% increase in abdominal visceral…