Investigation of perceived and calculated total energy expenditure in working adults undertaken by questionnaire

Background: Obesity is a major public health issue with many adults unable to maintain a healthy body weight (National Health Institute, 2011). Losing excessive body weight only occurs when energy intake (EI) is less than energy expenditure (EE) so gaining an understanding of energy expenditure is important. Underreporting total energy expenditure (TEE) is common amongst obese individuals with many judging food intake inaccurately (Davis, Curtis, Tweed & Patte, 2007). Therefore, this study aimed to investigate the effect of body mass index (BMI) on accuracy of perceived TEE compared to calculated TEE in working adults.Methods: A cross-sectional quantitative investigation was undertaken. An invitation to participate and information sheet were emailed to 150 adult employees of a healthcare company with a link to an online questionnaire. The questionnaire was designed for the study and comprised questions relating to anthropometry (2), demography (4) and perception of energy expenditure (2). The questionnaire was live for four weeks and no identifiable information was collected. Answers were used to calculate BMI (weight/height2), BMR (Henry, 2005) and TEE (Scientific Advisory Committee on Nutrition, 2011) and the difference between perceived and calculated TEE were calculated. Data were tested for normality using the Kolmogorov-Smirnov test and then relationships between variables were examined using Spearman rank correlation and differences between perceived and calculated TEE examined using Wilcoxon signed rank test (Campbell et al., 2010). The study had ethical approval (LMS/UG/UH/00158).Results: Fifty-two employees participated (14 men; 38 women), mean age 31.7±12.8 years. Significant relationships were identified between (a) calculated TEE and BMI (P=0.00, r=0.532), (b) difference between perceived and calculated TEE and BMI (P=0.01, r=0.353) but not between (c) perceived TEE and BMI (P= 0.24, r=-0.166). The difference between median perceived TEE and medium calculated TEE was not significant (2000kcal/d [500-3500kcal/d] vs 1758 [1569-2920kcal/d], P=0.122). Discussion: The finding that perceived TEE became increasingly different from calculated TEE as BMI increased suggests that people who are overweight our less able to estimate their energy requirements accurately. This agrees with previous research by Headrick et al., (2013) who investigated 978 adults in the USA. These findings do not prove that there is a causative link between inaccuracy in estimating TEE and weight gain and the role of weight in calculating both TEE and BMI must be considered. However, future research to examine perceived and measured TEE and BMI, the potential benefit of accurate estimations of TEE on body weight and the reasons for underestimation might contribute useful information to obesity management strategies.Conclusions: Inaccuracy of TEE perception, based on calculated values, increases with BMI in working