In 2025, Matthew J. Breit and the University of Colorado Anschutz Medical Campus did a secondary look at a 12-month trial with 36 adults trying to lose weight. They compared two groups: one cut calories every day, the other did 4:3 intermittent fasting (normal eating 4 days, low calories 3 days). They tracked eating habits, hunger feelings, and hormones like ghrelin (hunger signal) and leptin (fullness signal) at start, 3 months, and 12 months using surveys and blood tests.