Related Experiment Video

Updated: Jan 21, 2026

A Protocol for Roux-en-Y Gastric Bypass in Rats using Linear Staplers

A Protocol for Roux-en-Y Gastric Bypass in Rats using Linear Staplers

Published on: August 21, 2021

Evaluation of Advanced Bioimpedance Spectroscopy Models for Measuring Body Composition in Healthy Adults (NHANES

Abigail J Johnson¹, James R Matthie², Adam Kuchnia³

¹PhD, RD. University of Minnesota-Twin Cities, Department of Food Science and Nutrition, St. Paul, MN, USA.

BRASPEN Journal

|August 10, 2019

Abstract

Introduction:

Bioimpedance spectroscopy (BIS) devices utilize biophysical modeling to generate body composition data. The addition of body mass index (BMI) to modified Xitron-Hanai-based mixture equations improved BIS estimates of intracellular water (ICW), particularly at the extremes of BMI. A 3-compartment model for distinguishing excess fluid (ExF) from normally hydrated lean (NHLT) and adipose tissue may further improve BIS estimates.

Objective:

We aimed to validate a BIS approach based on the Chamney model for determining fat mass (FM) in healthy individuals (NHANES) and for measuring FM changes in individuals undergoing massive weight loss.

Methods:

Using adult NHANES 1999-2004 (2821 female, 3063 male) and longitudinal pre-to-post-RYGB (15F) data, we compared dual-energy-X-ray absorptiometry (DXA) and BIS for FM. We applied BIS adiposity-corrected values to Chamney equations for normally hydrated lean and adipose tissue (NHLT, NHAT) and FM. Method agreement was evaluated by correlations, paired t-tests, root mean square error (RMSE), Bland-Altman (B-A) analysis, and concordance correlation coefficients (CCC).

Results:

Method agreement between BIS and DXAFM was good in healthy adults (r=0.96, CCC=0.93, p<.0001), and pre-to-post-RYGB (r=0.93-0.98, CCC=0.81-0.86, p<.001). Although cross-sectional FM measures differed, FM change measures post-RYGB did not (35.6±8.9 vs. 35.2±9.2 kg, BIS vs. DXA) and agreed well (r=0.84, p<.0001). The 15 subjects with follow-up measurements at 1 year lost 11.5±9.8 kg FFM by DXA, but only 1.3±2.5 kg of NHLT by BIS, suggesting that the FFM loss may have been mostly adipose tissue water.

Conclusions:

Incorporation of the Chamney model into BIS algorithms is a major conceptual advancement for assessing and monitoring body composition. Its ability to differentiate ICW and extracellular water (ECW) in NHLT and NHAT, as well as excess ECW is promising, and would facilitate lean tissue monitoring in obesity and acute/chronic disease.

Keywords:

Bariatric Surgery Bioelectrical Impedance Body Composition Nutrition Surveys Obesity Weight Loss

More Related Videos

Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice

Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice

Published on: March 20, 2017

One-anastomosis Gastric Bypass OAGB in Rats

One-anastomosis Gastric Bypass OAGB in Rats

Published on: November 10, 2018

Related Concept Videos

Composite Bodies

Composite Bodies

A composite body is a body made up of multiple parts, connected to form a larger, unified object. Each part has its own weight and center of gravity, which must be considered to determine the center of gravity of the composite body. In cases where the density or specific weight is constant, the center of gravity coincides with the centroid.
Composite bodies have widespread applications in mechanical engineering, from automobiles to aircraft to rockets. For example, an automobile wheel comprises...

Composition of Body Fluids

Composition of Body Fluids

Water functions as a solvent accommodating various solutes, which can be categorized under electrolytes and non-electrolytes. Non-electrolytes are usually held together by covalent bonds, restricting them from dissociating in solution, thereby leading to a lack of electrically charged components upon dissolving in water. They are predominantly organic molecules, such as glucose, creatinine, and urea. Electrolytes, on the other hand, are compounds that can break down into ions in water.

Equipments Used to Measure Body Temperature

Equipments Used to Measure Body Temperature

Body temperature can be assessed using various devices and measured in Celsius or Fahrenheit.
Glass-bulb Thermometer:
Glass-bulb thermometers are hollow glass tubes with a bulb tip containing liquid such as ethanol or mercury. Historically, glass bulb mercury thermometers were the standard device to measure body temperature. Today, mercury thermometers are prohibited in many countries due to the hazardous effects of mercury and the risk of exposure if the glass bulb breaks. In general,...

Line Loss

Line Loss

The different configurations of source-load connections include wye (star) and delta connections. The relationship between line and phase voltages and currents varies depending on the configuration. When the source is supplying power, it is transmitted through the wires to the load, and during this transmission, some power is absorbed by the wires, leading to line loss.
Line loss impacts power delivery efficiency in a balanced three-phase circuit. The symmetry in such a circuit simplifies the...

Weighted Mean

Weighted Mean

While taking the arithmetic, geometric, or harmonic mean of a sample data set, equal importance is assigned to all the data points. However, all the values may not always be equally important in some data sets. An intrinsic bias might make it more important to give more weightage to specific values over others.
For example, consider the number of goals scored in the matches of a tournament. While computing the average number of goals scored in the tournament, it may be more important to...

Gastric Motility

Gastric Motility

Gastric motility is the coordinated contraction and relaxation of stomach muscles that convert ingested food into chyme, a semi-liquid substance ready for further digestion in the intestines. The process begins with the vagus nerve inducing the relaxation of the smooth muscles in the fundus and body of the stomach, allowing these regions to expand and accommodate up to approximately 1.5 liters of food and liquid.
Peristaltic Waves and Chyme Formation
Upon food entry, the stomach initiates...

Articles linked to this work by shared authors, journal, and citation graph.

A Tale of Two Cohorts: Comparing HPV Vaccination Barriers and Facilitators Among HIV-Negative and HIV-Positive Women in Tennessee.

International journal of environmental research and public health·2026

Shotgun metagenomic analysis reveals taxonomic and functional alterations in the gut microbiome across prodromal and symptomatic Lewy body disease.

Frontiers in microbiomes·2026

Strengthening the evidence base for precision medicine through the utilization of real-world data and real-world evidence: a narrative review from the U.S. perspective.

Personalized medicine·2026

The food matrix as a confounder in diet‒microbiome studies: methodological challenges and research gaps.

Gut microbes reports·2026

Malnutrition criteria and computed tomography-measured psoas muscle indices in adult liver transplant recipients.

Clinical nutrition ESPEN·2026

Motivated by mortality:-Women living with HIV and their perceptions regarding the HPV vaccination.

Exploratory research in clinical and social pharmacy·2026

See all related articles