Time-restricted feeding does not prevent adverse effects of palatable cafeteria diet on adiposity, cognition and gut microbiota in rats.

Time-restricted feeding (TRF) is a popular dietary strategy whereby daily food intake is limited to a <12h window. As little is known about the effects of TRF on cognitive and behavioral measures, the present study examined the effects of time-restricted (8h/day; zeitgeber time [ZT]12-20) or continuous access to a high-fat, high-sugar cafeteria-style diet (Caf; Caf and Caf-TRF groups; n=12 adult male Sprague-Dawley rats) or standard chow (Chow and Chow-TRF groups) on short-term memory, anxiety-like behavior, adiposity and gut microbiota composition over 13-weeks with daily food intake measures. TRF significantly reduced daily energy intake in Caf- but not chow-fed groups. In Caf-fed groups, TRF reduced the proportion of energy derived from sugar while increasing that derived from protein. Caf diet significantly increased weight gain, adiposity and fasting glucose within 4 weeks; TRF partially reduced these effects. Caf diet increased anxiety-like behavior in the Elevated Plus Maze in week 3 but not week 12, and impaired hippocampal-dependent place recognition memory in week 11; neither measure was affected by TRF. Global microbiota composition differed markedly between chow and Caf groups, with a small effect of TRF in rats fed chow. In both chow and Caf diet groups, TRF reduced microbiota alpha diversity measures of Shannon diversity and evenness relative to continuous access. Results indicate only limited benefits of TRF access to an obesogenic diet under these conditions, suggesting that more severe time restriction may be required to offset adverse metabolic and cognitive effects when using highly palatable diets.