Diet interventions commonly require establishing baseline ‘weight stable’ measures. Food diaries for measurement of energy intake (EI), may alter diet behaviours and result in a non-weight stable baseline. This study aimed to evaluate the adequacy of using weighed diet records during baseline phases of an intervention.
19 (9 F, 10 M) weight stable (±2 kg in 6 mths) participants recorded their EI via a weighed food diary and physical activity level (PAL) for 2 x 2 weeks. Body composition and resting energy expenditure (REE) were measured prior to commencing diet recording and at the end of each 2 wk period.
A small but statistically significant decrease in body weight occurred during diet record 1 (DR1) (Base: 81.6 ± 18.7 kg, DR1: 81.1 ± 18.6 kg, p<0.01), with no further change during diet record 2 (DR2) (DR2: 81.0 ± 18.5 kg, p=0.6). There were no changes in REE (p=0.9, CV: 3.5 ± 2.2%). Total Daily EE (TDEE) predicted from REE and PAL was highly consistent (DR1: 2692 ± 582 kcal/d, DR2: 2690 ± 618 kcal/d, p=0.9, CV: 3.3 ± 2.8%), as was reported EI (DR1: 2292 ± 539 kcal/d, DR2: 2318 ± 573 kcal/d, p=0.7, CV: 6.2 ± 4.9%). Reported EI was -400 ± 429 kcal/d and -372 ± 513 kcal/d lower than predicted TDEE during DR1 and DR2 respectively.
The use of weighed diet records had minimal effect on establishing weight stable measures. Mean weight change was within normal daily variation (-0.6 ± 1.1 kg). While measures of EE and reporting of EI were extremely consistent, the difference between values should lead to weight loss over time. The difference may result from overestimation of TDEE or underreporting of EI. Measures such as 24 hour Nitrogen excretion are necessary to confirm EI and the amount of underreporting.