Does feeding frequency, independent of total energy consumption, affect lizard digestive efficiency or growth?

Down-regulation of the digestive system between large meals is thought to afford energetic benefits to animals that feed infrequently. However, this idea has not been thoroughly tested. Thus, we assessed the realized benefits of infrequent feeding by examining how the timing of meal consumption influenced digestive efficiency and whole-body growth of juvenile Gila monsters, a binge-feeding lizard. All animals in our study received the same total energy intake for each feeding cycle, but meals were distributed differently over time among groups. One group had a 10-14-day period of down-regulation between meal sets while the other group had a constantly activated digestive system. The groups did not show differences in growth; however, differences in digestive efficiency for a specific meal indicate that feeding regime may have caused digestive adjustments (e.g. more efficient digestion) in one treatment group. Overall, our findings show that the energetic benefits of down-regulation may depend more on species, extent of digestive regulation, or duration of fasting than previously supposed.