Fasting and caloric restriction confer beneficial effects against caloric excess linked disease risks, including conferring anti-inflammatory effects. However, the mechanisms underpinning fasting and fasting mimetic diet mediated reduction in inflammatory biomarkers and inflammatory diseases are poorly characterized. To delineate how fasting mediates immune regulation, we performed, a clinical study exploring the effect of a 24-hour fast compared to 3 hours of refeeding. Subsequent flow cytometry, RNA-seq, bioinformatics, metabolomics and biochemical/genetic validation studies were performed on peripheral blood mononuclear cells (PBMCs) and from serum extracted from the human subjects in response to fasting and refeeding. The combination of bioinformatic pipeline interrogation and genetic validation studies identified three novel nutrient-dependent transcription factors that modulate T helper cell immune responsiveness. Our data point to multiple additional regulatory pathways that may be operational in this biology and suggest that the nutrient-load serum metabolome governs circulating immune cell programing.