Use of the cellular model of body composition to describe changes in body water compartments after total fasting, very low calorie diet and low calorie diet in obese men

Abstract

Introduction: The cellular model of body composition divides the body in body cell mass (BCM), extracellular solids and extracellular fluids. This model has been infrequently applied for the evaluation of weight loss (WL) programmes. Objectives: (1) To assess changes in body compartments in obese men undergoing fasting, very low calorie diet (VLCD) and low calorie diet (LCD); (2) to evaluate two cellular models for the determination of changes in BCM, fat mass (FM) and body fluids. Materials and methods: Three groups of six, obese men participated in a total fast (F) for 6 days, a VLCD (2.5 MJ per day) for 3 weeks or an LCD (5.2 MJ per day) for 6 weeks. Body composition was measured at baseline and after small (B5%) and moderate (B10%) WL. FM was measured using a four-compartment model. Total body water (TBW) and extracellular water (ECW) were, respectively, measured by deuterium and sodium bromide dilution and intracellular water (ICW) calculated by difference. Two cellular models were used to measure BCM, FM and body fluids distribution. Results: After about 5%WL changes in TBW were F ¼ À3.2±1.2 kg (Po0.01), VLCD ¼ À1.2±0.6 kg (Po0.01), LCD ¼ À0.3 ± 0.9 kg(n.s.). The contribution of TBW to total body mass loss was indirectly associated with FM loss. ECW increased during fasting ( þ 1.5±3.1 kg, n.s.), decreased during the VLCD (À2.0±1.5 kg, Po0.05) and remained unchanged at the end of the LCD (À0.3 ± 1.6 kg, n.s.). ICW significantly decreased during fasting (À4.7 ± 3.9 kg, Po0.05) but did not change in the LCD and VLCD groups. The loss of BCM was more significant in the fasting group and it was directly associated with changes in ICW. Conclusions: After a 6-day period of fasting we observed more ICW losses and less fat mobilization compared with VLCD and LCD. The cellular model of body composition is suitable for the characterization of changes in body fluids distribution during WL.

Accuracy of Specific BIVA for the Assessment of Body Composition in the United States Population

“…A high phase angle in patients with a low extracellular to intracellular water ratio, as assessed on the basis of NaBr isotope dilution, was already observed by other Authors [53]. The low ECW/ICW ratio can be related to high body cell mass [54], that is in turn related to high muscle mass [55]. In this study, bioelectrical values of athletic individuals effectively fell in the central part of the left area of the tolerance ellipse (low ECW/ICW ratio) and were significantly separated from lean ones, whose phase angle was lower and vector lengths higher (high ECW/ICW ratio) (Figure 3).…”

The potential of classic and specific bioelectrical impedance vector analysis for the assessment of sarcopenia and sarcopenic obesity

“…Moreover, the lower phase angle of sarcopenic individuals can be related to a higher ECW/ICW ratio21 (Buffa et al, unpublished data, 2012), a parameter that can be associated in relation with BCM,27 which is, in turn, related to muscle mass 28. According to specific BIVA, and in particular on the basis of similar R sp values in sarcopenic and nonsarcopenic individuals, the mean differences in the relative quantity of fat mass were not evident (with a p -value slightly above the significance level in women).…”

Imposed rate and extent of weight loss in obese men and adaptive changes in resting and total energy expenditure

“…Subjects were non-randomly allocated to three WL interventions (fasting, VLCD, LCD) with 106 a similar study design as previously described [21]. A description of the study protocol for 107 each WL intervention is provided in the online supplementary material (Figure S1-S3).…”