Researchers present weight loss research during ObesityWeek®

In late October, CU Anschutz Health and Wellness Center researchers traveled to Dallas, TX for The Obesity Society (TOS) conference during ObesityWeek.® In this annual event, leading experts converge to delve into cutting-edge science, clinical interventions, and policy approaches in the ongoing battle against the obesity epidemic. CU Anschutz Health and Wellness Center researchers Danielle Ostendorf, PhD, Mark Ezpeleta, PhD, Matt Breit, MS, RDN, and Emily Hill, PhD, RDN presented groundbreaking studies, shedding light on innovative dietary strategies for weight management, energy balance research methodology, and underlying mechanisms driving weight regain after weight loss. The following is a summary of the research they presented.

Modified Intermittent Fasting vs. Daily Caloric Restriction: A 1-Year Randomized Trial
Presented by: Danielle Ostendorf MS, ACSM-CEP, PhD

Authors: Danielle M. Ostendorf, Zhaoxing Pan, Seth A. Creasy, Anne E. Caldwell, Laura Grau, Adnin Zaman, Matthew J. Breit, Jared Dahle, Bryan Swanson, Kristen Bing, Liza Wayland, Shelby Panter, Jared J. Scorsone, Paul S. MacLean, Daniel H. Bessesen, Edward L. Melanson, and Victoria A. Catenacci

Most behavioral weight loss interventions use a single dietary strategy – restriction of calories every day. However, the majority of adults struggle to adhere to calorie restriction long-term. Researchers at the University of Colorado Anschutz Health and Wellness Center conducted a large, randomized controlled clinical trial to compare a 4:3 intermittent fasting approach to restricting calories every day. Participants included 165 adults (age 42±9 years, BMI 34.2±4.3 kg/m2, 74% female, 86% white, 24% Hispanic; mean±SD) who were randomized to receive either 4:3 intermittent fasting (80% restriction on 3, non-consecutive days per week) or daily caloric restriction (34.3% reduction in caloric intake every day) for 1 year. After 1 year, participants in the 4:3 intermittent fasting group lost significantly more weight compared to participants who restricted their calories daily (-7.7±1.0 vs -4.8±1.1 kg; p=0.04). 4:3 intermittent fasting was more effective for weight loss over 1 year compared to restricting calories daily.



Change in Diet Quality Over 1 Year of Daily Caloric Restriction Versus Modified Intermittent Fasting

Presenter: Emily Hill, PhD, RDN

Authors: Emily B Hill, Danielle M Ostendorf, Zhaoxing Pan, Jared J Scorsone, Liza Wayland, Kristen Bing, Paul S MacLean, Edward L Melanson, Daniel H Bessesen, Victoria A Catenacci



Emily Hill, PhD, RDN, a Postdoctoral Fellow working with Victoria Catenacci, MD, presented research evaluating the effect of a one-year behavioral weight loss intervention on diet quality among healthy adults with overweight and obesity. Two dietary strategies for weight loss, daily caloric restriction and intermittent fasting, were used. For both groups, dietary intake was assessed before and after the intervention via self-reported seven-day diet records. Data were used to calculate Healthy Eating Index (HEI) scores, which measure adherence to the US Dietary Guidelines and are reflective of overall diet quality. There were no significant changes in total HEI scores for either intervention group, although there were trends for improved adherence to recommendations for foods high in nutrient density and low in energy density. Findings indicate dietary strategies focused on caloric restriction may not lead to improved adherence to evidence-based dietary recommendations, suggesting diet quality should be targeted during weight loss to enhance health benefits.



Estimating Total Daily Energy Expenditure Over 6 Months in a Behavioral Weight Loss Intervention

Presented by: Matt Breit, MS, RDN

Authors: Zhaoxing Pan, Danielle M Ostendorf, Jared Dahle, Daniel Bessesen, Paul MacLean, Victoria Catenacci, Edward Melanson, Seth Creasy 


Matt Breit, MS, RDN, a Predoctoral Student working with Victoria Catenacci, MD and Edward Melanson, PhD presented research evaluating the creation and implementation of a regression model to estimate total daily energy expenditure (TDEE) over 6-months of a behavioral weight loss intervention among healthy adults with overweight or obesity. Doubly labeled water (DLW) was used to assess TDEE, dual-energy x-ray absorptiometry (DXA) was used to measure fat mass and fat-free mass, and indirect calorimetry was used to measure resting metabolic rate (RMR) at months 0, 1, and 6. The month 1 timepoint was included to account for the expected rapid weight loss induced during negative energy balance. Data were used to develop an equation to model TDEE and compared against a previously published equation and a time-weighted criterion model equation. Findings indicate our new model equation correlated well with the criterion model and performed similarly to a previously published model. Use of this TDEE model equation may improve estimations of TDEE during weight loss interventions.



Effects of Short-Term Overfeeding on 24H Energy Expenditure in Weight Reduced Adults with Obesity

Presented by: Mark Ezpeleta, PhD

Authors: Corey A. Rynders, Mark Ezpeleta, Sheila Steinke, Emilee Mickaliger, Melissa Mamele, Edward L. Melanson, Daniel H. Bessesen



Mark Ezpeleta, PhD, is a Postdoctoral Fellow working with Daniel Bessesen, MD, presented research on the impact of short-term overfeeding on 24h energy expenditure in adults with obesity compared to those who achieve 8-12% weight loss. Long-term weight loss maintenance success rates are low, due in part to adaptive changes in energy expenditure that favor weight regain. The study randomized volunteers with obesity into diet (DIET) or diet and exercise (DIET+Ex) groups. Post-weight loss, participants were studied for 23 h in a whole room calorimeter under two conditions: eucaloric (EU, consuming daily calorie needs) and overfeeding (OF, 40% calorie increase). Compared to the EU condition, OF significantly increased 24h energy expenditure in the control group but not in the DIET and DIET+Ex groups. These findings suggest adaptive changes in energy expenditure may contribute to weight regain during weight loss maintenance, regardless of physical activity.



The research presented at ObesityWeek® the CU Anschutz Health and Wellness Center researchers unveils insights into effective approaches to obesity management. From the use of intermittent fasting in promoting weight loss to advancements in estimating total daily energy expenditure and the impact of different dietary strategies on overall diet quality, these studies contribute valuable knowledge to the ongoing efforts to combat obesity.