9:00 am - 10:00 am
1-040 Li Ka Shing Centre, University of Alberta, Oborowsky Degner Seminar Hall (1-040) , Edmonton
Oborowsky Degner Seminar Hall (1-040), Li Ka Shing Centre (LKS)
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES PhD Final Exam Seminar by Leticia Radin Pereira. This seminar is open to the general public to attend.
Thesis Topic: Evaluation of Energy Metabolism, Weight Retention and Appetite in Postpartum Women
Seminar Abstract: Postpartum weight retention (PPWR) is an important risk factor for long-term obesity. Accurate assessment and understanding of energy expenditure and other metabolic characteristics of postpartum women may improve weight management following childbirth. The overall aims of this research were to explore key metabolic characteristics associated with weight retention during this life stage; and to explore the validity of resting energy expenditure (REE) predictive equations, as well as the accuracy of current recommendations in predicting total energy expenditure (TEE).
This was a longitudinal observational study involving women at three (3M-PP; n=52) and nine months postpartum (9M-PP; n=49); some measurements were only undertaken at 9M-PP. Energy expenditure was measured by whole body calorimetry (WBC). Body composition was determined using dual-energy X-ray absorptiometry. Appetite sensations (i.e. hunger, prospective food consumption [PFC], fullness, satiety) were individually assessed using visual analogue scales, and subsequently combined to calculate a composite appetite score (CAS). Lactation pattern was measured using a 3-day breastfeeding diary including a 24-h infant test weighing protocol. Cardiorespiratory fitness was determined through a fitness test measuring the predicted maximal volume of oxygen consumption (pV̇O2 max). REE was compared to 17 predictive equations; measured TEE was compared to the Estimated Energy Requirements/DRI equation (EERDRI).
This research showed that REE at 3M-PP was negatively associated with PPWR at 3M-PP (mean β ± SE: -0.570 ± 0.196, P=0.004) and 9M-PP (-0.688 ± 0.252, P=0.006). PPWR was negatively associated with pV̇O2max (-0.02 ± 0.01, P= 0.047). Women’s perceptions of appetite were associated with PPWR (fullness: -2.97 ± 0.72, P<0.001; satiety: -2.75 ± 0.81, P=0.002; hunger: 2.19 ± 1.02, P=0.039, PFC: 2.19± 0.91, P=0.021, and CAS: 0.34 ± 0.09, P=0.001). Several REE predictive equations performed well at a group level at both time points. At an individual level, high rates of inaccuracy and wide limits of agreement were observed. Compared to TEE, EERDRI yielded inaccurate results for 33% of women, however improved accuracy was observed when accounting for individual lactation patterns.
In conclusion, energy expenditure, cardiorespiratory fitness, and appetite were associated with body weight regulation. Additionally, commonly used predictive equations did not accurately estimate energy expenditure at an individual level. Collectively, these findings have the potential to contribute to 1) the development of future weight management strategies in postpartum women by targeting appetite and energy metabolism; and 2) the formation of energy recommendations tailored to the needs of individual postpartum women. These may also assist in promoting appropriate body weight and improving care during this life stage.
Leticia Radin Pereira – PhD with Dr. Carla Prado and Dr. Linda McCarger