Background: We tested the hypothesis that ad libitum food intake shows corrective responses over periods of 1-5 d. Design: This was a prospective study of food intake in women. Methods: Two methods, a weighed food intake and a measured food intake, were used to determine daily nutrient intake during 2wk in 20 women. Energy expenditure with the use of doubly labeled water was done contemporaneously with the weighed food-intake record. The daily deviations in macronutrient and energy intake from the average 7-d values were compared with the deviations observed 1, 2, 3, 4, and 5 d later to estimate the corrective responses. Results: Both methods of recording food intake gave similar patterns of macronutrient and total energy intakes and for deviations from average intakes. The intraindividual CVs for energy intake ranged from +/- 12% to +/- 47% with an average of +/- 25%. Reported energy intake was 85.5-95.0% of total energy expenditure determined by doubly labeled water. Significant corrective responses were observed in food intakes with a 3- to 4-d lag that disappeared when data were randomized within each subject. Conclusions: Human beings show corrective responses to deviations from average energy and macronutrient intakes with a lag time of 3- 4 d, but not 1-2 d. This suggests that short-term studies may fail to recognize important signals of food-intake regulation that operate over several days. These corrective responses probably play a crucial role in bringing about weight stability. Am J Clin Nutr 2008; 88: 1504-10.