Figure 1. Caloric restriction and time restricted feeding are popular dietary interventions that implement periodic fasting. Both diets improve insulin sensitivity, but only CR significantly improves glucose homeostasis. This unexpected uncoupling of highly intertwined insulin sensitivity and glucose homeostasis can be explained through a selective effect of the diets on tissue insulin sensitivity. The diets differ in the magnitude of calories and duration of fasting. Two meal per day CR will reduce the duration of fasting and may elucidate the relative contributions of caloric intake and fasting on glucose homeostasis. (See more details in the text).