title: Nighttime snacking reduces whole body fat oxidation and increases LDL cholesterol in healthy young women.
abstract: The increase in obesity and lipid disorders in industrialized countries may be due to irregular eating patterns. Few studies have investigated the effects of nighttime snacking on energy metabolism. We examined the effects of nighttime snacking for 13 days on energy metabolism. Eleven healthy women (means ± SD; age: 23 ± 1 yr; body mass index: 20.6 ± 2.6 kg/m(2)) participated in this randomized crossover trial for a 13-day intervention period. Subjects consumed a specified snack (192.4 ± 18.3 kcal) either during the daytime (10:00) or the night time (23:00) for 13 days. On day 14, energy metabolism was measured in a respiratory chamber without snack consumption. An oral glucose tolerance test was performed on day 15. Relative to daytime snacking, nighttime snacking significantly decreased fat oxidation (daytime snacking: 52.0 ± 13.6 g/day; nighttime snacking: 45.8 ± 14.0 g/day; P = 0.02) and tended to increase the respiratory quotient (daytime snacking: 0.878 ± 0.022; nighttime snacking: 0.888 ± 0.021; P = 0.09). The frequency of snack intake and energy intake, body weight, and energy expenditure were not affected. Total and low-density lipoprotein (LDL) cholesterol significantly increased after nighttime snacking (152 ± 26 mg/dl and 161 ± 29 mg/dl; P = 0.03 and 76 ± 20 mg/dl and 83 ± 24 mg/dl; P = 0.01, respectively), but glucose and insulin levels after the glucose load were not affected. Nighttime snacking increased total and LDL cholesterol and reduced fat oxidation, suggesting that eating at night changes fat metabolism and increases the risk of obesity.
authors.affiliation: Health Care Food Research Laboratories, Kao Corporation, Bunka, Sumida-ku, Tokyo, Japan. hibi.masanobu@kao.co.jp
authors.forename: Masanobu
authors.initials: M
authors.lastname: Hibi
authors.forename: Ayumi
authors.initials: A
authors.lastname: Masumoto
authors.forename: Yuri
authors.initials: Y
authors.lastname: Naito
authors.forename: Kahori
authors.initials: K
authors.lastname: Kiuchi
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Yoshimoto
authors.forename: Mai
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Katashima
authors.forename: Jun
authors.initials: J
authors.lastname: Oka
authors.forename: Shinji
authors.initials: S
authors.lastname: Ikemoto
mesh_terms: D000704:Analysis of Variance; D001066:Appetite; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition; D002151:Calorimetry; D008078:Cholesterol, LDL / Q000097:blood*; D002940:Circadian Rhythm; D018592:Cross-Over Studies; D002149:Energy Intake; D004734:Energy Metabolism; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D007564:Japan; D050356:Lipid Metabolism; D009765:Obesity / Q000209:etiology / Q000378:metabolism; D010084:Oxidation-Reduction; D019518:Postprandial Period; D062410:Snacks; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D008078:Cholesterol, LDL; D007328:Insulin