Nighttime eating: commonly observed and related to weight gain in an inpatient food intake study.
BACKGROUND
Nighttime food intake has rarely been studied in inpatient settings and only one study observed a relation between self-reported nighttime eating and weight gain.


OBJECTIVE
We investigated the prevalence of nighttime eating and its effect on weight change.


METHODS
Healthy nondiabetic Pima Indians (n = 117; 67 M, 50 F) and whites (n = 43; 29 M, 13 F) were admitted to a clinical research unit. After consuming a standardized diet for 3 d, participants ate ad libitum from a computer-operated vending machine that recorded the time of food selection. Energy intake was calculated as mean kcal/d. Follow-up weight was available for 94 volunteers.


RESULTS
Fifty-five subjects (36%) were nighttime eaters (NEs; persons who ate between 2300 and 0500 on > or =1 of the 3 d). Prevalence was similar among whites and Pima Indians (37% and 35%, respectively). There were no significant differences in body mass index or percentage body fat between NEs and non-NEs. NEs consumed more calories per day (4758) than did non-NEs (4244; P = 0.02), but the percentage of calories from macronutrients did not differ. NEs consumed approximately 15% (690 kcal) of their daily energy during nighttime episodes. After control for baseline weight and follow-up time (x +/- SD: 3.4 +/- 1.8 y), NEs (n = 29) gained more weight (6.2 kg) than did non-NEs (n = 65; 1.7 kg; P = 0.03).


CONCLUSIONS
Nighttime eating was common, and it predicted weight gain. It remains to be determined whether this behavior indicates abnormal sleep patterns leading to nighttime wakefulness and food intake in those prone to weight gain.
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Phoenix, AZ 85016, USA. gmarci@niddk.nih.gov
Marci E
ME
Gluck
Colleen A
CA
Venti
Arline D
AD
Salbe
Jonathan
J
Krakoff
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D004435:Eating / Q000502:physiology*; D002149:Energy Intake / Q000502:physiology*; D001068:Feeding and Eating Disorders / Q000150:complications* / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005518:Food Preferences; D006801:Humans; D007198:Indians, North American; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000209:etiology*; D015995:Prevalence; D012737:Sex Factors; D012893:Sleep Wake Disorders / Q000503:physiopathology; D013997:Time Factors; D015430:Weight Gain