The Energy Metabolism of Man During Overfeeding

Munro, Hamish N.

doi:10.1079/bjn19500056

Cited by 11 publications

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References 16 publications

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“…The continuous measurement of the 24 h energy expenditure of subjects who have over-fed for several weeks is needed to check this point, and a fuller discussion of the factors which may be involved in the response to over-feeding is given by Dauncey (19794. During over-feeding in the present study there was on average a significant increase in the RMR at least 14 h after the last meal, whereas Gulick (1922) Glick et al (1977) all concluded that the basal metabolic rate (BMR) was unaltered during over-feeding. However, of these studies the first two (Gulick, 1922;Munro, 1950) were each on only one subject and in the former the BMR was measured only during over-feeding and then compared with normal values in standard tables. Glick et al (1977) based their conclusions on mean values from four overweight and four normal weight individuals, but inspection of their results indicates that the normal subjects showed an increase in 'BMR' while those who were over-weight showed a decline.…”

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confidence: 99%

Metabolic effects of altering the 24 h energy intake in man, using direct and indirect calorimetry

Dauncey

1980

Br J Nutr

118

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I. The metabolic effects of increasing or decreasing the usual energy intake for only I d were assessed in eight adult volunteers. Each subject lived for 28 h in a whole-body calorimeter at 26" on three. separate occasions of high, medium or low energy intake. Intakes (meanfsm) of 13830f475 (high), 8400*510 (medium) and 3700f359 (low) kJ/24 h were eaten in three meals of identical nutrient composition.2. Energy expenditure was measured continuously by two methods: direct calorimetry, as total heat loss partitioned into its evaporative and sensible components; and indirect calorimetry, as heat production calculated from oxygen consumption and carbon dioxide production. For the twenty-four sessions there was a mean difference of only 1.zfo.14 (SEM) % between the two estimates of 24 h energy expenditure, with heat loss being less than heat production. Since experimental error was involved in both estimates it would be wrong to ascribe greater accuracy to either one of the measures of energy expenditure.3. Despite the wide variation in the metabolic responses of the subjects to overeating and under-eating, in comparison with the medium intake the 24 h heat production increased significantly by 10 % on the high intake and decreased by 6 % on the low intake. Mean (~S E M ) values for 24 h heat production were 8770f288, 7896f297 and 7495f253 kl on the high, medium and low intakes respectively. The effects of overeating were greatest at night and the resting metabolic rate remained elevated by 12 % 14 h after the last meal. By contrast, during undereating the metabolic rate at night decreased by only I %. 4. Evaporative heat loss accounted for an average of 25 % of the total heat loss at each level of intake. Changes in evaporative heat loss were f14 % on the high intake and -10 % on the low intake. Sensible heat loss altered by +9 % and -5 % on the high and low intakes respectively. 5.It is concluded that (a) the effects on 24 h energy expenditure of over-feeding for only I d do not differ markedly from those estimated by some other workers after several weeks of increasing the energy intake; (b) the resting metabolic rate, measured at least 14 h after the last meal, can be affected by the previous day's energy intake; (c) the zone of ambient temperature within which metabolism is minimal is probably altered by the level of energy intake.There is considerable disagreement about the metabolic effects of over-eating in man. The controversy is concerned particularly with the effect on the resting metabolic rate (RMR) at least 1 2 h after the last meal: some workers (Miller et al. 1967;Strong et al. 1967) reported no change, while others (Durnin & Norgan, 1969; Apfelbaum et al. 1971) reported an increase after several weeks of over-feeding. There is also much interest in the extent to which some people may adapt to over-feeding by increasing their energy expenditure so that there is little or no increase in weight or less weight gain than expected. Owing to inadequate methodology, many studies on the effects of an altered ...

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