1. ¹Research Unit for Dietary Studies, Institute of Preventive Medicine, Copenhagen University Hospital, Copenhagen K, Denmark
2. ²Danish Epidemiology Science Centre, Institute of Preventive Medicine, Copenhagen University Hospital, Copenhagen K, Denmark
3. ³Research Centre for Prevention and Health, Glostrup University Hospital, Philadelphia, USA
4. ⁴Department of Psychiatry, University of Pennsylvania, Philadelphia, USA

Correspondence: Dr BL Heitmann, Research Unit for Dietary Studies, Institute of Preventive Medicine, Kommunehospitalet, DK-1399 Copenhagen K, Denmark. E-mail: BLH@ipm.hosp.dk

Received 30 June 2003; Revised 4 April 2004; Accepted 25 April 2004; Published online 27 July 2004.

Abstract

OBJECTIVE: To examine the association between the habit of eating at night, and the 5-y preceding and 6-y subsequent weight changes in a middle-aged population, with particular focus on the obese.

DESIGN: Prospective study with initial examination of the cohort in 1982–83, re-examination in 1987–88 and a third examination in 1992–93.

SUBJECTS: The Danish MONICA cohort includes an age- and sex-stratified random sample of the population from the Western part of the Copenhagen County. Out of 2987 subjects participating in 1987–88, a total of 1050 women and 1061 men had been examined in 1982–83, and 1993–94 too. Subjects working night shifts were excluded.

MEASUREMENTS: Night eating in 1987–88, 5-y preceding and 6-y subsequent weight change.

RESULTS: In total, 9.0% women and 7.4% men reported 'getting up at night to eat'. Obese women with night eating experienced an average 6-y weight gain of 5.2 kg (P=0.004), whereas only 0.9 kg average weight gain was seen among obese women who did not get up at night to eat. No significant associations were found among all women, or between night eating and the 5-y preceding weight change for women. Night eating and weight change were not associated among men.

CONCLUSION: Night eating was not associated with later weight gain, except among already obese women, suggesting that getting up at night to eat may be a contributor to further weight gain among the obese.