International Journal of Obesity (2004) 28, 653–660 & 2004 Nature Publishing Group All rights reserved 0307-0565/04 $25.00 www.nature.com/ijo
PAPER
Decreased thermic effect of food after an irregular compared with a regular meal pattern in healthy lean women
HR Farshchi1*, MA Taylor1 and IA Macdonald1
1 Centre for Integrated Systems Biology and Medicine, Institute of Clinical Research and School of Biomedical Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
OBJECTIVES: To investigate the impact of irregular meal frequency on body weight, energy intake, appetite and resting energy expenditure in healthy lean women. DESIGN: Nine healthy lean women aged 18–42 y participated in a randomised crossover trial consisting of three phases over a total of 43 days. Subjects attended the laboratory at the start and end of phases 1 and 3. In Phase 1 (14 days), subjects were asked to consume similar things as normal, but either on 6 occasions per day (regular meal pattern) or follow a variable predetermined meal frequency (between 3 and 9 meals/day) with the same total number of meals over the week. In Phase 2 (14 days), subjects continued their normal diet as a wash-out period. In Phase 3 (14 days), subjects followed the alternative meal pattern to that followed in Phase 1. Subjects recorded their food intake for three predetermined days during the irregular period when they were eating 9, 3 and 6 meals/day. They also recorded their food intake on the corresponding days during the regular meal pattern period. Subjects fasted overnight prior to each laboratory visit, at which fasting resting metabolic rate (RMR) was measured by open-circuit indirect calorimetry. Postprandial metabolic rate was then measured for 3 h after the consumption of a milkshake test meal (50% CHO, 15% protein and 35% fat of energy content). Subjects rated appetite before and after the test meal. RESULTS: There were no significant differences in body weight and 3-day mean energy intake between the regular and irregular meal pattern. In the irregular period, the mean energy intake on the day when 9 meals were eaten was significantly greater than when 6 or 3 meals were consumed (P ¼ 0.0001). There was no significant difference between the 3 days of the regular meal pattern. Subjective appetite measurement showed no significant differences before and after the test meal in all visits. Fasting RMR showed no significant differences over the experiment. The overall thermic effect of food (TEF) over the 3 h after the test meal was significantly lower after the irregular meal pattern (P ¼ 0.003). CONCLUSION: Irregular meal frequency led to a lower postprandial energy expenditure compared with the regular meal frequency, while the mean energy intake was not significantly different between the two. The reduced TEF with the irregular meal frequency may lead to weight gain in the long term. International Journal of Obesity (2004) 28, 653–660. doi:10.1038/sj.ijo.0802616 Published online 16 March 2004 Keywords: irregular meal frequency; energy expenditure; energy intake; thermic effects of food; regular meal pattern; appetite; hunger and satiety
Introduction
The prevalence of obesity continues to increase around the world, in spite of a widespread desire to control body weight. Body weight, or more precisely body energy content, can only increase when energy intake exceeds energy expendi-
*Correspondence: HR Farshchi, E 72, School of Biomedical Sciences, Queen’s Medical Centre, Clifton Boulevard, Nottingham NG7 2UH, UK. E-mail: mbxhrf@nottingham.ac.uk Received 8 July 2003; revised 9 December 2003; accepted 28 December 2003
ture for a prolonged period. Meal pattern has been identified as a factor influencing body weight.1,2 Fabry et al1 suggested a negative relationship between meal frequency and body weight in the 1960s. Many investigators have attempted to evaluate further the effect of meal frequency on body weight.3–17 An effect could
