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Biomedical subjects

P V Sukhatme

Publications and source records attributed to P V Sukhatme.

15 recordsLinked to original sources
PubMed1989

Nutritional adaptation and variability.

In current nutrition literature man's requirement for energy for a given status and pattern of physical activity and body mass is fixed. Available experimental data on the other hand show that it is variable and self-regulated over a considerable range. This homoeostatic range is associated with covariance of man's genotype with local environmental effect under a sustained perturbation of common external environment. The implication is that man can have his intake anywhere in the range without being under nutritional stress. Below the lower limit of this range man is under energy stress, growth is retarded and man adapts to small body size. Unlike the homoeostatic range, this long-term adaptation is heritable, but there is no evidence that work output equals energy intake in adaptation to low intake. On the contrary, small subjects on a lower plane of nutrition are found to be metabolically more efficient. Evidence is cited to show that it is the decrease in BMR in subjects with low intake which plays a major role in facilitating a higher level of metabolic efficiency for subjects undergoing energy stress.

Adaptation, Physiological↗
PubMed1982

Autoregulatory homestatic nature of energy balance.

This paper proposes a new theory regarding energy regulation in man. Current theory states that similar adults have similar energy requirements when engaged in similar activities. As a corollary, if activities remain constant and energy intake is altered, weight will change. This theory has been unable to explain the repeated observations that individuals of the same sex and age and engaged in similar work show a mean weekly coefficient of variation in energy intake of about 16% without significant fluctuations in body weight. Furthermore, repeated studies have failed to show any individual "pattern" relating energy intake to output. This lack of pattern has been attributed either to methodological error or to the fact that human energy requirements cannot be determined by current methods. This paper shows that neither case is correct. The explanation lies in the stochastic stationary nature of energy requirements. Because of the nature of significant intraindividual variations noted in all experiments, "requirement" is a dynamic concept, and energy balance will vary as a matter of course about zero. The implications of this for the individual, society, and policy are enormous and are discussed herein.

Body Weight↗
PubMedDate not supplied

Performance of normal-weight and underweight men with marginal changes in energy intake.

This study compares the continuous response of six underweight (UW) (body mass index [BMI] < 18 kg/m2) and six normal-weight (NW) (20 < BMI < 25) men of similar age to a modest but sustained level of underfeeding and overfeeding. Habitual energy intake over 4 wk, body composition, and basal metabolic rate (BMR) were measured under metabolic-ward conditions. NW subjects were heavier by 9 kg and had 5% more body fat than UW subjects. The average BMR of UW subjects was 7.5% lower than NW subjects in absolute terms and also per kilogram fat-free mass per day but was higher by 8% when expressed per kilogram body weight per day. Three NW and three UW subjects were given a diet with 10% less energy than their habitual intake for 4 wk. They were brought back to the normal level of feeding for another 4 wk. Finally, they were overfed by 10% for 4 wk. This sequence was reversed in the remaining six subjects. Changes in body weight, BMR, and energy balance were assessed. UW subjects showed a quick and vigorous reduction in BMR (13.4%) during the 1st wk of underfeeding compared with NW subjects (8.1%). In the later weeks, the reduction was 8% in UW and 7% in NW subjects. Furthermore, UW subjects showed a tendency to resist a decrease in body weight (mean loss 180 g), unlike NW subjects (mean loss 730 g). With overfeeding, the mean increase in BMR for UW was higher (7.4%) than for NW (5.3%) subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗