Visceral fat and weight loss in obese subjects : relationship to serum lipids, energy expenditure and sex hormones

This thesis describes the relationships between visceral fat accumulation and serum lipids, energy expenditure, and sex hormone levels in healthy obese men and premenopausal women undergoing weight loss therapy. The subjects, aged 27-51 years, with an initial body mass index of 28-38 kg/m 2, received a controlled diet for 13 weeks providing a 4.2 MJ/day energy deficit. Magnetic resonance imaging was used to quantify fat depots.In women but not in men, visceral fat accumulation was associated with a less favourable serum lipid profile independent of age and body fat percentage. In addition, in women only, visceral fat predominance was positively related to resting metabolic rate (RMR) and diet- induced thermogenesis (DIT) as well as to a relatively increased androgenicity. In obese men, no relationship could be found between visceral fat accumulation and any of the sex hormone levels.The mean weight reduction of 12.2 ± 3.5 (SD) kg due to the energy-deficit diet, resulted in larger reductions in serum levels of total cholesterol, LDL cholesterol, and triglycerides and a larger increase in the HDL cholesterol/LDL cholesterol ratio in men compared with women. Men with an initially larger visceral fat depot than women did not lose more body weight, but they lost more visceral fat than women. Comparison of these average changes between both sexes suggests a potential role of visceral fat loss in improving the serum lipid profile. While in women, a loss of visceral fat was related to an increased HDL cholesterol, a more general beneficial effect of visceral fat loss was not seen using correlation analyses within each sex. In women but not in men, visceral fat accumulation before weight loss was associated with improvement of HDL cholesterol and triglyceride levels after weight loss. In women only, a reduction in the visceral fat depot also seems to be accompanied by a relative reduction in androgenicity regardless of total body fat loss.In this study, the effect of weight loss alone on serum lipids could be separated from the effect of dietary fat modification usually accompanying a dietary weight loss treatment. The favourable effect of weight loss per se seems to be considerable in optimizing the serum lipid profile of obese subjects and even greater than that of dietary fat modification.It is concluded that there may be gender differences in the associations between visceral fat accumulation and serum lipids, energy expenditure (RMR and DIT), and sex hormone levels in healthy moderately obese subjects. In addition, particularly healthy moderately obese women with a visceral fat predominance benefit from a dietary weight loss treatment with respect to their serum lipid profile and sex hormone levels. In healthy moderately obese men, the critical role of the visceral fat depot could not be confirmed.

Bibliographic Details

Main Author:	Leenen, R.
Other Authors:	Hautvast, J.G.A.J.
Format:	Doctoral thesis biblioteca
Language:	English
Published:	Landbouwuniversiteit Wageningen
Subjects:	adipose tissue, biometry, consumption patterns, energy requirements, fats, food hygiene, nutrition, nutritional state, obesity, overweight, sex hormones, biometrie, consumptiepatronen, energiebehoeften, geslachtshormonen, obesitas, overgewicht, vetten, vetweefsel, voeding, voedingstoestand, voedselhygiëne,
Online Access:	https://research.wur.nl/en/publications/visceral-fat-and-weight-loss-in-obese-subjects-relationship-to-se
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