Limited microglial metabolic improvement with time-restricted feeding in diet-induced obesity

Time-restricted eating has shown promise for improving metabolic health in obese humans. In this study, we investigated how time-restricted feeding (TRF) at different times of the day affects the microglial brain immune function using Wistar rats. We found that in high-fat diet (HFD)-induced obesity, TRF during the active phase of rats is effective in reducing fat mass, enhancing the rhythmicity of the microglial transcriptome, and preventing an increase in microglial cell number. These effects are not seen with TRF during the resting phase. However, the HFD-induced activation of microglial metabolic pathways was not reversed by TRF in either the active or resting phase, indicating that the reprogrammed microglial metabolism in obesity is a persistent cellular functional change that might form a metabolic memory and play a role in body weight regain upon discontinuation of restricted eating.