The organisation of timing in mammalian circadian clocks optimally coordinates behavior and physiology with daily environmental cycles. Chronic consumption of a high-fat diet alters circadian rhythms, but the acute effects on circadian organisation are unknown. To investigate the proximate effects of a high-fat diet on circadian physiology, we examined the phase relationship between central and peripheral clocks in mice fed a high-fat diet for 1 week. By 7 days, the phase of the liver rhythm was markedly advanced (by 5 h), whereas rhythms in other tissues were not affected. In addition, immediately upon consumption of a high-fat diet, the daily rhythm of eating behavior was altered. As the tissue rhythm of the suprachiasmatic nucleus was not affected by 1 week of high-fat diet consumption, the brain nuclei mediating the effect of a high-fat diet on eating behavior are likely to be downstream of the suprachiasmatic nucleus.
The effects of 1 week of high-fat diet consumption on tissue and behavioral circadian rhythms in mice were investigated. The phase of the liver rhythm was advanced, while rhythms in other tissues were not affected by high-fat diet. High-fat diet also immediately altered the daily rhythm of eating behavior. As the rhythm of the suprachiasmatic nucleus (SCN) was not affected, the brain nuclei mediating the effect of high-fat diet on eating behavior are likely downstream of the SCN.