Differential effects of time-restricted feeding on circadian locomotor activity, food intake and body weight gain in BALB/cJ and C57BL/6J mice

Time-restricted feeding is used to study the food-entrainable oscillator in mammals, yet there is considerable inconsistency in procedures for imposing restrictions. Additionally, the majority of rodent studies being used to model this strategy employ C57BL/6 J laboratory mice, which likely do not represent the diversity in human circadian responses. We compared effects of time-restricted feeding (TRF) and periodic phase shifts of the light-dark cycle on food intake, weight maintenance and distribution of locomotor activity in TRF and ad-lib fed C57BL/6 J and BALB/cJ mice. Imposing TRF initially produced significantly greater weight loss in BALB/cJ mice, the degree of which depended on the procedure employed. TRF yielded caloric restriction throughout the duration of the experiment in BALB/cJ but not C57BL/6 J mice, and resulted in significantly greater re-distribution of daily locomotor activity relative to the light-dark cycle in BALB/cJ mice. Food intake and weight gain in BALB/cJ mice also varied with time of feeding. These findings emphasize that the same restricted feeding procedure can produce substantially different physiological and behavioral outcomes that must be considered when developing studies on time-restricted feeding in mice.