Effects of periodic intake of a high-caloric diet on body mass and leptin resistance

The effects of continuous or intermittent access to a high-caloric (HC) diet, always offered in addition to standard chow, on body mass and leptin resistance were analyzed in female C57BL/6J mice. Susceptibility for diet-induced obesity (DIO) was apparent from the marked preference for the HC diet. Continuous HC diet feeding of mice at 4 weeks of age induced leptin resistance within 2 weeks and massive gains in body mass, although with increasing inter-individual variability in the inbred strain considered to be isogenic. In adult mice receiving HC diet for the first time, leptin treatment failed to reduce energy intake first after 11 days of HC diet feeding, but became effective again within 3 days after HC diet withdrawal. In mice with a history of several preceding periods of access to the HC diet totalling > 30 days, supplementary HC diet abolished the anorectic effect of leptin treatment within only 3 days and it reappeared not earlier than 11 days after HC diet withdrawal. Thus, in the investigated DIO-prone mouse strain both, the loss of responsiveness to leptin under HC diet and its recovery after HC diet withdrawal strongly depended on the dietary history. Recovery from leptin resistance during periods of intermittent chow feeding was associated with losses of body mass that did not completely compensate for the obesity-inducing effect of the preceding HC diet.