Prior day's intake has macronutrient-specific delayed negative feedback effects on the spontaneous food intake of free-living humans.

A fundamental issue in understanding how energy balance is accomplished involves comprehending how changes in intake affect subsequent intake. This was investigated in free-living humans by reanalyzing the data previously collected from 733 adults who were paid to maintain a 7-d diary of everything they ate and when they ate it. Food energy intake during a day was found to only mildly affect intake on the subsequent day (mean r = -0.07, P < 0.001), but was more strongly negatively related to intake occurring on the second (mean r = -0.18, P < 0.001) and third day (mean r = -0.10, P < 0.001) afterward. Each macronutrient was shown to have a maximal negative relationship with subsequent intake of that same macronutrient, with 2-d lag mean autocorrelations equal to -0.11, P < 0.001 for carbohydrate, equal to -0.18, P < 0.001 for fat, and equal to -0.13, P < 0.001 for protein. These effects on daily intake were found to result from separate negative feedback effects on meal size and frequency. The results suggest that intake affects subsequent intake by persistently setting a long-term bias that, integrated over time, produces a net shift in intake.