The Effect of Timing of Food Intake on Body Fatness

• Published in: Journal of the American Dietetic Association 1999-09, Vol.99 (9), p.A122-A122
• Main Authors: Hillyard, T.R., Mitchell, C.O., Crase, D.R., Clemens, L.E., Slawson, D.L., Watson, J.M.
• Format: Article
• Language: English
• ISSN: 0002-8223; 1878-3570
• DOI: 10.1016/S0002-8223(99)00822-6

This study examined the association of timing of food intake on body fatness, measured by: body mass index (BMI) and dual-energy X-ray absorptiometry (DEXA). Data were taken from seventy-five women from one of two federally funded studies. Subjects who under-reported dietary intake, which had been validated against resting energy expenditure (REE) as assessed via indirect calorimetry, were not part of the present study. Four days (2 weekdays and 2 weekend days) of diet records from each subject were analyzed for kilocalorie and macronutrient content of each of four time periods. The time periods consisted of: 1) morning (midnight to 10:59 a.m.), 2) afternoon (11:00 a.m. – 4:59 p.m.), 3) evening (5:00 p.m. – 7:59 p.m.), and 4) night (8:00 p.m. – 11:59 p.m.). Nutrient analyses were performed using the DINE nutrient analysis program. Percent body fat as measured by DEXA, and heights and weights were obtained, and BMI was calculated (weight in kg/height in m2). Analyses of covariance and regression analyses were then performed to determine the association between timing of food intake and body fatness. The majority of people consumed more of their kilocalories before 8:00 p.m. than after 8:00 p.m. Neither timing of meals nor fat intake, nor number of eating episodes per day, were associated with BMI or DEXA, even when adjusting for total kilocalories. BMI and DEXA were positively correlated, but BMI underestimated body fatness compared to DEXA. Therefore, eating at night does not appear to influence body fatness, which is consistent with other studies. While strongly correlated with DEXA, BMI should be used with caution, since it may underestimate body fatness.