Food and fluid intake and hydration status does not affect ultrasound measurements of subcutaneous adipose tissue in active adults.

Objectives: To investigate the impact of acute food and fluid intake or hydration status on the standardised brightness-mode ultrasound measurement of subcutaneous adipose tissue thickness.

Design: Thirty active adults (female n = 10) participated in a randomised cross over study.

Methods: Participants completed three body composition assessment sessions via standardised brightness-mode ultrasound and Dual-energy X-ray absorptiometry. Participants were assessed under standardised presentation during 'food only' and 'food plus water' sessions at baseline and reassessed after their allotted intake. 'Hypohydration plus water' was undertaken in a hypohydrated state at baseline and reassessed after water intake.

Results: The sum of eight subcutaneous adipose tissue thickness was lower when measured after 'food only' or 'food plus water' compared to baseline (-0.1 to -0.9 mm; p < 0.01). However, these changes were less than the 95% confidence interval of the technical error of measurement of the investigator. Body mass, dual-energy x-ray absorptiometry total and trunk mass, lean mass and trunk lean mass estimates increased (p < 0.01) following 'food only' or 'food plus water', and decreased with hypohydration (p < 0.01). Total and regional fat mass estimates were not impacted.

Conclusions: The sum of eight subcutaneous adipose tissue thickness measured via standardised brightness-mode ultrasound was unaffected by acute food and fluid consumption or hydration status changes. Comparatively, these interventions altered dual-energy x-ray absorptiometry body composition estimates, especially that of lean mass components. Standardised brightness-mode ultrasound can therefore be used to monitor changes in fat patterning when standardised client presentation is not practically achievable.