title: Reliability of BOD POD Measurements Remains High After a Short-Duration Low-Carbohydrate Diet.
abstract: The purpose of the current study was to determine whether expected changes in body weight via a 3-day low-carbohydrate (LC) diet will disrupt the reliability of air displacement plethysmography measurements via BOD POD. Twenty-four subjects recorded their typical diets for 3 days before BOD POD and 7-site skinfold analyses. Subjects were matched for lean body mass and divided into low-CHO (LC) and control (CON) groups. The LC group was given instruction intended to prevent more than 50 grams/day of carbohydrate consumption for 3 consecutive days, and the CON group replicated their previously recorded diet. Body composition measurements were repeated after dietary intervention. Test-retest reliability measures were significant (p < .01) and high for body fat percentage in both the LC and the CON groups (rs = .993 and .965, respectively). Likewise, skinfold analysis for body fat percentage reliability was high in both groups (rs = .996 and .997, respectively). There were significant differences between 1st and 2nd BOD POD measurements for body mass (72.9 ± 13.3 vs. 72.1 ± 13.0 kg [M ± SD]) and body volume (69.0 ± 12.7-68.1 ± 12.2 L) in the LC group (p < .05). However, there were no differences (p > .05) in BOD POD-determined body fat percentage, lean body mass, or fat mass between the 1st and 2nd trial in either group. Body composition measures via BOD POD and 7-site skinfolds remain reliable after 3 days of an LC diet despite significant decreases in body mass.
authors.affiliation: Department of Physical Therapy and Human Movement Science, Sacred Heart University, Fairfield, CT.
authors.forename: Beau Kjerulf
authors.initials: BK
authors.lastname: Greer
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Edsall
authors.forename: Anna E
authors.initials: AE
authors.lastname: Greer
mesh_terms: D000328:Adult; D001823:Body Composition; D001835:Body Weight; D050528:Diet, Carbohydrate-Restricted; D005260:Female; D006801:Humans; D008297:Male; D010991:Plethysmography / Q000295:instrumentation*; D015203:Reproducibility of Results; D013997:Time Factors