Heymsfield Sb

Energy balance measurement: when something is not better than nothing

Energy intake (EI) and physical activity energy expenditure (PAEE) are key modifiable determinants of energy balance, traditionally assessed by self-report despite its repeated demonstration of considerable inaccuracies. We argue here that it is time to move from the common view that self-reports of EI and PAEE are imperfect, but nevertheless deserving of use, to a view commensurate with the evidence that self-reports of EI and PAEE are so poor that they are wholly unacceptable for scientific research on EI and PAEE. While new strategies for objectively determining energy balance are in their infancy, it is unacceptable to use decidedly inaccurate instruments, which may misguide health-care policies, future research and clinical judgment. The scientific and medical communities should discontinue reliance on self-reported EI and PAEE. Researchers and sponsors should develop objective measures of energy balance.

Six-compartment body composition model: inter-method comparisons of total body fat measurement.

OBJECTIVE: To compare 16 currently used total body fat methods to a six-compartment criterion model based on in vivo neutron activation analysis.DESIGN: Observational, inter-method comparison study.SUBJECTS: Twenty-three healthy subjects (17 male and 6 female).MEASUREMENTS: Total body water (TBW) was measured by tritium dilution; body volume by underwater weighing (UWW); total body fat and bone mineral by dual-energy X-ray absorptiometry (DXA), total body potassium (TBK) by whole-body 40K counting; total body carbon, nitrogen, calcium, phosphorus, sodium and chlorine by in vivo neutron activation analysis; skinfolds/circumferences by anthropometry (Anth); and resistance by single-frequency bioimpedance analysis (BIA).RESULTS: The average of total body fat mass measurements by the six-compartment neutron activation model was 19.7±10.2 kg (mean±s.d.) and comparable estimates by other methods ranged from 17.4–24.3 kg. Although all 16 methods were highly correlated with the six-compartment criterion model, three groups emerged based on their comparative characteristics (technical error, coefficient of reliability, Bland-Altman analysis) relative to criterion fat estimates, in decreasing order of agreement: 1. multi-compartment model methods of Baumgartner (19.5±9.9 kg), Heymsfield (19.6±9.9 kg), Selinger (19.7±10.2 kg) and Siri-3C (19.6±9.9 kg); 2. DXA (20.0±10.8 kg), Pace-TBW (18.8±10.1 kg), Siri-2C (20.0±9.9 kg), and Brozek-UWW (19.4±9.2 kg) methods; and 3. Segal-BIA (17.4±7.2 kg), Forbes-TBN (21.8±10.5 kg), Durnin-Anth (22.1±9.5 kg), Forbes-TBK (22.9±11.9 kg), and Steinkamp-Anth (24.3±9.5 kg) methods.CONCLUSION: Relative to criterion fat estimates, body composition methods can be organized into three groups based on inter-method comparisons including technical error, coefficient of reliability and Bland-Altman analysis. These initial groupings may prove useful in establishing the clinical and research role of the many available fat estimation methods.

Body composition in children and adults by air displacement plethysmography

Objectives: Air displacement plethysmography (ADP) may provide a partial alternative to body density (Bd) and therefore body composition measurement compared to conventional hydrodensitometry (Hd) in children. As there are no evaluation studies of ADP in children, this study had a two-fold objective: to compare Bd estimates by ADP and Hd; and to compare fat estimates by both ADP and Hd to fat estimates by another reference method, dual energy X-ray absorptiometry (DXA).Setting: Obesity Research Center, St. Luke’s/Roosevelt Hospital, New York, USA.Subjects: One hundred and twenty subjects (66 females/54 males) who ranged in age from 6–86 y and in body mass index (BMI, kg/m2) from 14.1–40.0  kg/m2 met study entry criteria.Study Design: Cross-sectional study of healthy children (age≤19 y) and adult group for comparison to earlier studies. Each subject completed ADP, Hd, and DXA studies on the same day. Only subjects with subjectively-judged successful Hd studies were entered into the study cohort.Results: There was a high correlation between Bd by ADP and Hd (Bd Hd=0.11+0.896×Bd ADP; r=0.93, SEE=0.008 g/cm3, P<0.0001), although the regression line slope and intercept differed significantly from 1 and 0, respectively. Additional analyses localized a small-magnitude Bd bias in the child (n=48) subgroup. Both ADP and Hd%fat estimates were highly correlated (r>0.9, P<0.0001) with%fat by DXA in child and adult subgroups. Bland–Altman analyses revealed no significant%fat bias by either ADP or Hd vs DXA in either children or adults, although a bias trend (P=0.11) was detected in the child subgroup.Conclusion: With additional refinements, the air displacement plethysmography system has the potential of providing an accurate and practical method of quantifying body fat in children as it now does in adults.Sponsorship: This study was in-part supported by NIH Grants RR00645, NIDDK 42618 and NIDDK 37352.

A novel soy-based meal replacement formula for weight loss among obese individuals: a randomized controlled clinical trial.

Objective: To assess the efficacy and safety of a low calorie soy-based meal replacement program for the treatment of obesity.Design: A 12-week prospective randomized controlled clinical trial.Setting: Outpatient weight control research unit.Subjects: One hundred obese (28<BMI≤41 kg/m2) volunteers between the ages of 35 and 65 y. Seventy-four participants completed the trial.Interventions: Participants were randomized to either the meal replacement treatment group (n=50; 240 g/day, 1200 kcal/day) or control group (n=50). Both groups at baseline received a single dietary counseling session and a pamphlet describing weight loss practices.Main outcome measures: Weight, body fat, serum lipid concentrations.Results: By intent-to-treat analysis, the treatment group lost significantly more weight than the control group (7.00 vs 2.90 kg; P<0.001) and had a greater change in total (22.5 vs 6.8 mg/dl; P=0.013) and LDL cholesterol (21.2 vs 7.1 mg/dl; P<0.009). Among completers only, the treatment group again lost more weight (7.1 kg; n=37 vs 2.9 kg; n=37; P=0.0001) and had a greater reduction in total cholesterol (26.1 mg/dl; n=37 vs 6.7 mg/dl; P=0.0012) and a greater change in LDL cholesterol (21.6 vs 5.5 mg/dl; P=0.0025). (For any given degree of weight loss, the reduction in LDL cholesterol was significantly greater in the treatment group.) Treatment was well tolerated and no serious side effects were detected.Conclusions: Use of this soy-based meal replacement formula was effective in lowering body weight, fat mass and in reducing LDL cholesterol beyond what could be expected given the weight lost.Sponsorship: This research was funded by Nutripharma. Dr Allison is a member of the United Soybean Boards Scientific Advisory Panel and Chair of the Research Grants Committee.

Techniques used in the measurement of body composition: an overview with emphasis on bioelectrical impedance analysis.

The study of human body composition is now a distinct research area consisting of three interconnected parts: the five-level model and associated rules that govern the relations between components, body-composition methodology, and biological factors that influence body composition. In this overview we summarize fundamental concepts that relate to the five-level model and body-composition methods. We show how these concepts can be used to outline the essential features needed to critically evaluate the bioelectrical impedance analysis method. Body-composition research is a rapidly expanding area and in-depth systematic evaluation of new methods is a vital aspect of the fields growth.

Intermuscular adipose tissue rivals visceral adipose tissue in independent associations with cardiovascular risk

Background:The metabolic implications of intermuscular adipose tissue (IMAT) are poorly understood compared to those of visceral adipose tissue (VAT) even though the absolute quantities of both depots are similar in many individuals.Objective:The aim was to determine the independent relationship between whole-body IMAT and cardiovascular risk factor parameters.Design:Whole body magnetic resonance imaging (MRI) was used to quantify total skeletal muscle (SM), total adipose tissue (TAT) of which IMAT, defined as the AT visible by MRI within the boundary of the muscle fascia, is a sub-component. Fasting serum measures (n=262) of glucose, total cholesterol (T-Chol), high-density lipoprotein cholesterol (HDL-Chol), triglycerides (TG), protein bound glucose (PBG, n=206) and insulin (n=119) were acquired in healthy African-American (AA, n=78) and Caucasian (Ca, n=109) women (body mass index (BMI) 26.5±5.7 kg/m2; 44.4±16.4 years) and men (39 AA, 62 Ca; BMI 25.6±3.5 kg/m2; 45.6±17.4 years). General linear models identified the independent effects of IMAT after covarying for SM, VAT, TAT, race, sex and two-way interactions.Results:Significant independent associations were observed for IMAT with glucose (P<0.001), PBG (P<0.001) and T-Chol (P<0.05). The association of IMAT with cholesterol differed by race in such a manner that for a unit increase in IMAT, T-Chol increased more rapidly in Ca compared to AA (P<0.05). TG, HDL-Chol and insulin had no independent association with IMAT.Conclusion:The strong independent associations of IMAT with fasting glucose and PBG suggest that IMAT may be related to glucose metabolism; however, IMAT is also associated with T-Chol in Ca.

Truncal fat in relation to total body fat: influences of age, sex, ethnicity and fatness

Objective:To investigate the influence of age, sex, ethnicity and total fatness on central obesity in four ethnic populations.Design:Cross-sectional analysis of study subjects enrolled from 1993 to 2005.Subjects:A multi-ethnic (Caucasian (CA), African-American (AA), Hispanic-American (HA) and Asian (As)) convenience sample of 604 men and 1192 women (aged 18–96 years, body mass index 15.93–45.80 kg/m2).Measurements:Total body fat (TBF) and truncal fat were measured by dual-energy X-ray absorptiometry. General linear regression models were used to test for independent associations with log10-transformed truncal fat.Results:For all ethnicities, men had a lower percent body fat and more truncal fat than women. Log10-transformed truncal fat increased with TBF approximately as a square root function. At older ages, there was a greater amount of truncal fat in CA, HA and As men (∼0.20–0.25 kg/decade) with the effect more pronounced in AA men (∼0.33 kg/decade). For women, the increment of truncal fat per decade was reduced in CA and AA women (∼0.07 kg) compared with As and HA women (∼0.33 kg). Adjusted for mean values of covariates in our sample, AA had less truncal fat than As.Conclusion:The accumulation of truncal fat is strongly related to age, ethnicity and total fatness in both men and women.

Inverse Association between Fruit and Vegetable Intake and BMI even after Controlling for Demographic, Socioeconomic and Lifestyle Factors

Objective: To estimate fruit and vegetable (FV) intake levels of US adult population and evaluate the association between FV intake and BMI status after controlling for confounding demographic, socioeconomic and lifestyle factors. We also sought to identify moderating factors. Methods: We used 2007 Behavior Risk Factors Surveillance System (N > 400,000) data. FV intake was dichotomized as ≧5 servings (FV5+) versus <5 servings/ day. BMI status was categorized as normal, overweight, and obese. Identification of moderators was performed by testing interactions between BMI status and other variables using bivariate analyses followed by multiple logistic regression analysis incorporating complex survey sampling design features. Results: Only 24.6% of US adults consumed ≧5 servings per day and less than 4% consumed 9 or more servings. Overweight (% FV5+ = 23.9%) and obese (21.9%) groups consumed significantly less FV than the normal-weight (27.4%) group (p < 0.0001). This inverse association remained significant even after controlling for potential confounding factors. Multivariate analysis identified five significant moderators (p < 0.0001) after controlling for all evaluated variables: race, sex, smoking status, health coverage, and physical activity. Notably, physically inactive obese males tended to consume the least FV (% FV5+ = 14.7%). Conclusion: Current US population FV intake level is below recommended levels. The inverse association between FV intake and obesity was significant and was moderated by demographic, socioeconomic status, and lifestyle factors. These factors should be considered when developing policies and interventions to increase FV intake.

Fat-free mass index: changes and race/ethnic differences in adulthood.

Objective:Nutritional status is assessed by measuring BMI or percent body fat (%fat). BMI can misclassify persons who carry more weight as fat-free mass and %fat can be misleading in cases of malnutrition or in disease states characterized by wasting of lean tissue. The fat-free mass index (FFMI) is proposed to assess body composition in individuals who have a similar body composition but differ in height allowing identification of those suffering from malnutrition, wasting or those that possess a relatively high muscle mass. The purpose was to determine whether the FFMI differs in a group of racially/ethnically diverse adults.Design:Cross-sectional.Subjects:Subjects were a multi-ethnic sample (Caucasian, CA; African American, AA; Hispanic, HIS and Asian, AS) of 1339 healthy males (n=480) and females (n=859) ranging in age from 18—110 years. Total body fat, total fat-free mass and bone mineral density were estimated using dual energy X-ray absorptiometry.Results:FFMI differed among the four ethnic groups (P⩽0.05) for both genders. A curvilinear relationship was found between age and FFMI for both genders although the coefficients in the quadratic model differed between genders (P⩽0.001) indicating the rate of change in FFMI differed between genders. The estimated turning point where FFMI started to decline was in the mid 20s for male and mid 40s for female participants. An age × gender interaction was found such that the rate of decline was greater in male than female participants (P⩽0.001). For both genders, FFMI was greatest in AA and the least in AS (P⩽0.001). There was no significant interaction between race and age or age2 (P=0.06). However, male participants consistently had a greater FFMI than female participants (P⩽0.001).Conclusions:These findings have clinical implications for identifying individuals who may not be recognized as being malnourished based on their BMI or %fat but whose fat-free mass corrected for height is relatively low.

Electrocardiographic QTC interval: short-term weight loss effects.

OBJECTIVE: Prolongation of the QTc interval is a risk factor for ventricular arrhythmias and sudden death. There is a correlation between body mass index (BMI) and QTc, with longer intervals observed in obese subjects. Dieting and weight loss on selected diets are also associated with prolongation of the QTc interval, although the mechanisms and risk factors of this syndrome are not clearly established. The aim of the current investigation was to determine if short-term weight loss over seven days while living on a metabolic ward influences cardiac repolarization as indicated by QT interval duration. DESIGN AND SUBJECTS: The elctrocardiogram QT, RR, and QTc (QT/RR0.5) intervals were assessed in 30 healthy obese (BMI>27 kg/m2) men and women ingesting a balanced 1120 kcal/d formula diet (23% kcal as fat and 52 g protein/d). RESULTS: Weight loss (3.9±1.7 kg) over seven days had no measurable effect on the RR interval and there was a significant (P=0.02) shortening of the QT interval (mean±s.d., 0.395±0.028–0.386±0.027 s) and borderline significant (P=0.11) shortening of the QTc (0.411±0.028–0.404±0.025 s) interval. The QTc interval normalized in three subjects with prolonged baseline QTc (>0.44 s). A statistically significant (P=0.007) reduction in systolic blood pressure early in the course of weight loss (day 2) accompanied the electrocardiographic changes. CONCLUSION: These results fail to support the development of cardiac repolarization abnormalities in obese patients who ingest a nutritionally balanced low calorie diet over seven days. A significant reduction in QT interval duration and amelioration of abnormally prolonged baseline QTc intervals suggest improved cardiac repolarization with early weight loss.