In a 2013 study, two groups of overweight women were randomly assigned to eat a large breakfast or a large dinner. Both ate 1400 calories per day; only the timing of the largest meal was changed. The breakfast group lost far more weight than the dinner group. Why? Despite following similar diets and eating about the same amount, the dinner group had a much larger overall rise in insulin. An earlier 1992 study showed similar results. In response to the same meal given either early or late in the day, the insulin response was 25 to 50 percent greater in the evening.
