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Background The normal-weight BMI range (18.5–24.9 kg/m2) includes adults with body shape and cardiometabolic disease risk features of excess adiposity, although a distinct phenotype developed on a large and diverse sample is lacking. Objective To identify demographic, behavioral, body composition, and health-risk biomarker characteristics of people in the normal-weight BMI range who are at increased risk of developing cardiovascular and metabolic diseases based on body shape. Methods Six nationally representative waist circumference index (WCI, weight/height0.5) prediction formulas, with BMI and age as covariates, were developed using data from 17,359 non-Hispanic (NH) white, NH black, and Mexican-American NHANES 1999–2006 participants. These equations were then used to predict WCI in 5594 NHANES participants whose BMI was within the normal weight range. Men and women in each race/Hispanic-origin group were then separated into high, medium, and low tertiles based on the difference (residual) between measured and predicted WCI. Characteristics were compared across tertiles; P values for significance were adjusted for multiple comparisons. Results Men and women in the high WCI residual tertile, relative to their BMI and age-equivalent counterparts in the low tertile, had significantly lower activity levels; higher percent trunk and total body fat (e.g. NH white men, X ± SE, 25.3 ± 0.2% compared with 20.4 ± 0.2%); lower percent appendicular lean mass (skeletal muscle) and bone mineral content; and higher plasma insulin and triglycerides, higher homeostatic model assessment of insulin resistance (e.g. NH white men, 1.45 ± 0.07 compared with 1.08 ± 0.06), and lower plasma HDL cholesterol. Percent leg fat was also significantly higher in men but lower in women. Similar patterns of variable statistical significance were present within sex and race/ethnic groups. Conclusions Cardiometabolic disease risk related to body shape in people who are normal weight according to BMI is characterized by a distinct phenotype that includes potentially modifiable behavioral health risk factors. [ABSTRACT FROM AUTHOR]

Background: Body mass index (BMI) is formulated on the assumption that body weight (BW) scales to height with a power of 2 (BW∝height(2)), independent of sex and race-ethnicity. Powers differing from 2 are observed in studies of selected samples, thus raising the question if BMI is a generalizable metric that makes BW independent of height across populations., Objectives: The objectives were to test the hypothesis that adult BW scales to height with a power of 2 independent of sex and race-ethnicity and to advance an understanding of BMI as a measure of shape by extending allometric analyses to waist circumference (WC)., Design: We conducted cross-sectional subject evaluations, including body composition, from the NHANES and the Korean NHANES (KNHANES). Variations of the allometric model (Y = αX(β)) were used to establish height scaling powers (β ± SE) across non-Hispanic white and black, Mexican American, and Korean men and women., Results: Exploratory analyses in population samples established age and adiposity as important independent determinants of height scaling powers (i.e., β). After age and adiposity in the next series of analyses were controlled for, BW scaling powers were nonsignificantly different between race/ethnic groups within each sex group; WC findings were similar in women, whereas small but significant between-race differences were observed in the men. Sex differences in β values were nonsignificant except for BW in non-Hispanic blacks and WC in Koreans (P < 0.05). Nationally representative powers for BW were (NHANES/KNHANES) 2.12 ± 0.05/2.11 ± 0.06 for men and 2.02 ± 0.04/1.99 ± 0.06 for women and for WC were 0.66 ± 0.03/0.67 ± 0.05 for men and 0.61 ± 0.04/0.56 ± 0.05 for women., Conclusions: Adult BW scales to height with a power of ∼2 across the 8 sex and race/ethnic groups, an observation that makes BMI a generalizable height-independent measure of shape across most populations. WC also follows generalizable scaling rules, a finding that has implications for defining body shape in populations who differ in stature., (© 2014 American Society for Nutrition.)

Background: To date, there is no consensus regarding adult cutoffs of percentage of body fat or estimated cutoffs on the basis of nationally representative samples with rigorous body-composition measurements., Objective: We developed cutoffs of percentage of body fat on the basis of the relation between dual-energy x-ray absorptiometry-measured fat mass and BMI (in kg/m(2)) stratified by sex, age, and race-ethnicity by using 1999-2004 NHANES data., Design: A simple regression (percentage of body fat = β(0) + β(1) × 1 ÷ BMI) was fit for each combination of sex (men and women), 3 age groups (18-29, 30-49, and 50-84 y of age), and 3 race-ethnicity groups (non-Hispanic whites, non-Hispanic blacks, and Mexican Americans). Model fitting included a consideration of complex survey design and multiple imputations. Cutoffs of percentage of body fat were computed that corresponded to BMI cutoffs of 18.5, 25, 30, 35, and 40 on the basis of estimated prediction equations., Results: R(2) ranged from 0.54 to 0.72 for men (n = 6544) and 0.58 to 0.79 for women (n = 6362). In men, the percentage of body fat that corresponded to a BMI of 18.5, 25, 30, 35, and 40 across age and racial-ethnic groups ranged from 12.2% to 19.0%, 22.6% to 28.0%, 27.5% to 32.3%, 31.0% to 35.3%, and 33.6% to 37.6%, respectively; the corresponding ranges in women were from 24.6% to 32.3%, 35.0% to 40.2%, 39.9% to 44.1%, 43.4% to 47.1%, and 46.1% to 49.4%, respectively. The oldest age group had the highest cutoffs of percentage of body fat. Non-Hispanic blacks had the lowest cutoffs of percentage of body fat. Cutoffs of percentage of body fat were higher in women than in men., Conclusions: Cutoffs of percentage of body fat that correspond to the current US BMI cutoffs are a function of sex, age, and race-ethnicity. These factors should be taken into account when considering the appropriateness of levels of percentage of body fat.

Background: Body weight scales to height with a power of ≈2, thus forming the basis of body mass index (weight/height(2)). The corresponding scaling of body composition to height has not been established in a representative sample of US adults., Objective: The aim of the study was to examine the scaling of weight, fat, fat-free mass, and bone mineral content to height., Design: Adult non-Hispanic white (NHW), non-Hispanic black (NHB), and Mexican American National Health and Nutrition Examination Survey (NHANES) participants were included in allometric analyses if they had complete age, weight, height, and body-composition data as measured by dual-energy X-ray absorptiometry. Powers of height in allometric regression models were developed for each measure and adjusted for age., Results: The analyses included 13,183 subjects (6699 NHW, 3015 NHB, and 3469 Mexican American). The scaling of weight to height across sex-race groups provided powers (mean ± SE) ranging from 1.85 ± 0.12 in Mexican American women to 2.48 ± 0.17 in Mexican American men. Powers of height for body composition similarly ranged widely and were often outside the 95% CI for a power of 2. Of the 3 body-composition measures, the mean age-adjusted powers of height rounded to 2 as the nearest integer in 16 of 18 sex-race groups., Conclusions: Adult weight and body composition scale to height with variable age-adjusted powers that are sometimes outside the 95% CI for a power of 2 but frequently round to 2 as the nearest integer. These observations have implications for developing height-adjusted body-composition indexes.

Background: Weight scales as height squared, which is an observation that forms the basis of body mass index (weight/height(2)). If, and how, circumferences, including waist circumference (WC) and hip circumference (HC), scale to height remains unclear, but this is an important consideration when developing normative ranges or applying WC/height and HC/height as risk indexes., Objective: The study aim was to examine the scaling of weight, WC, and HC to height in NHANES (National Health and Nutrition Examination Survey) III participants., Design: Subjects were adult non-Hispanic white, non-Hispanic black, and Mexican American men (n = 7422) and nonpregnant women (n = 7999) who had complete demographic and anthropometric data. In addition to height, allometric models were developed for each measure that controlled for age, race, and self-reported health status., Results: After adjustment for age and race, weight scaled to height in men and women with mean (±SEE) powers of 2.29 ± 0.11 and 1.80 ± 0.07, respectively (both P < 0.001). Although univariate circumference-height models were weak or nonsignificant, when adjusted for age and race WC and HC scaled to height with powers of 0.76 ± 0.08 and 0.45 ± 0.05, respectively, in men and 0.80 ± 0.05 and 0.53 ± 0.04, respectively, in women (all P < 0.001). Age- and race-adjusted incremental increases in circumferences ranged from 0.2 to 0.5 cm per centimeter increase in height. Both WC/height and HC/height scaled negatively to height in men and women, and WC/HC scaled negatively to height in women only (all P < 0.001). Health status-adjusted models were similar., Conclusions: Circumferences and related ratios scale significantly to height, notably after adjustment for age and race, across subjects who are representative of the US population. These observations have implications for the clinical and epidemiologic use of these anthropometric measures and indexes.

Background: Cross-sectional data indicate an inverse relation between breakfast consumption and child weight. It has been suggested that skipping breakfast may adversely affect appetite in children, which could lead to overeating later in the day., Objective: The aim of this study was to test the effects of consuming breakfast compared with omitting breakfast on appetite ratings and energy intake at subsequent meals in 8- to 10-y-old children., Design: Twenty-one children participated in 2 test visits during which they were served either a compulsory breakfast or no breakfast. On both visits, subjects were also served lunch, which was consumed ad libitum. Subjects rated their appetite throughout the morning; parents completed food records that captured children's intake for the remainder of the day., Results: There was no significant main effect of breakfast condition on energy intake at lunch (P = 0.36) or throughout the remainder of the day (P = 0.85). There was a significant main effect of breakfast condition (P = 0.04) on total daily energy intake, which indicated that on the day when the subjects did not eat breakfast, they consumed 362 fewer calories over the course of the day than when they did eat breakfast. On the day when no breakfast was served, subjects indicated that they were significantly hungrier, less full, and could consume more food before lunch than on the day when they did eat breakfast (P < 0.001)., Conclusions: Omitting breakfast affected children's appetite ratings but not their energy intake at subsequent meals. The dissonance between children's subjective ratings of prospective consumption and their actual intake should be further examined.