OBJECTIVE: The objective was to assess the quantitative agreement between a 4-day food record and a 24-hour dietary recall in young men. METHODS: Thirty-four healthy men aged 18-25 years had their food intake estimated by 4-day food record within one week following 24-hour dietary recall in a cross-sectional study. Resting metabolic rate was assessed by indirect calorimetry and Energy Expenditure was estimated by physical activity records completed simultaneously with food intake records. The validity of food records was determined by direct comparison of Energy Intake and Energy Expenditure (95% confidence interval for Energy Intake/Energy Expenditure). RESULTS: There were good agreements between the measurements of energy and macronutrient intakes by 24-hour dietary recall and 4-day food record at the group level, but not at the individual level. Compared to energy expenditure, about 20% and 9% of participants underreported their Energy Intake by 4-day food record and 24-hour dietary recall, respectively. Over 30% of underreporters of Energy Intake estimated by 24-hour dietary recall underreported Energy Intake estimated by 4-day food record. CONCLUSION: Both diet methods, 24-hour dietary recall and 4-day food record, may be used to collect data at the group level, but not at the individual level. Both methods, however, appear to underestimate Energy Intake. Underreporting may be subject-specific and appears that is more difficult to retrieve valid dietary data from some people than others.