Physical Activity Not Enough To Ward Off Weight Gain Interview with:

Lara Dugas, PhD, MPH, FTOS Public Health Sciences Loyola University Chica

Dr. Lara Dugas

Lara Dugas, PhD, MPH, FTOS
Public Health Sciences
Loyola University Chicago What is the background for this study?

Response: Our NIH-funded study is led by Dr. Amy Luke, Public Health Sciences, Loyola University Chicago, and is titled “Modeling the Epidemiologic Transition study” or METS. It was initiated in 2010, and 2,500 young African-origin adults were recruited from 5 countries, spanning the Human Development Index (HDI), a WHO index used to rank countries according to 4 tiers of development. The 5 countries include the US, Seychelles, Jamaica, South Africa, and Ghana. Within each country 500 young adults, 25-45 yrs., and 50% male, were recruited and followed prospectively for 3 years. Each year, contactable participants completed a health screening, body composition, wore an activity monitor for 7 days, and told researchers everything they had eaten in the preceding 24hrs. Our main research questions we were trying to answer were to understand the impact of diet and physical activity on the development of obesity, and cardiovascular disease in young adults. It was important to have countries spanning the HDI, with differences in both country-level dietary intake and physical activity levels. What are the main findings?

Response: After 2 yrs. of follow-up, we found that countries with higher prevalence’s of overweight/obesity at baseline, e.g. US, did not experience as much yearly weight gain, as countries with lower prevalence of overweight and obesity, e.g. Ghana and South Africa. More importantly, and contrary to popular belief, we found that neither baseline physical activity levels nor time spent being sedentary, were not associated with weight change. In fact young adults who met the US Surgeon General Physical Activity Guidelines, 30min/day of moderate-to-vigorous physical activity, were as likely to gain weight, as those adults not meeting the physical activity guideline. Only baseline starting, age and gender (men vs. women) were significantly associated with weight gain. What should readers take away from your report?

Response: Over the last two decades there has been a lot of effort spent suggesting that the reason that the obesity prevalence has increased so significantly, and in particular in developed countries such as the US, is because we have become much less active during our day-to-day activities, particularly during working hours, as a result of automation and vehicles. As opposed to more emphasis on the obesogenic food environment. In our study, given that even young adults meeting the physical activity guideline were as likely to gain weight as those who did not, suggests that both sides of the energy balance spectrum must be considered. Further it is clear that if readers want to prevent future weight gain, it is not enough to simply engage in physical activities. What recommendations do you have for future research as a result of this study?

Response: From our study, it is clear that population groups experience weight gain differently, and “a one size fit all” approach may not work on a global scale. It is also clear that future studies need to consider both sides of the energy balance spectrum, addressing both energy intake as well as energy expenditure, although dietary intake studies are notoriously difficult to complete at a population-level. Is there anything else you would like to add?

Response: Physical activity and, by proxy, cardiorespiratory fitness are critically important predicators of overall morbidity and mortality. Their importance for weight loss, however, is not as clear. Public health professionals and clinicians should be mindful that simply recommending increased physical activity to address the obesity epidemic may not be effective. No disclosures to report. Thank you for your contribution to the community.


Lara R. Dugas, Stephanie Kliethermes, Jacob Plange-Rhule, Liping Tong, Pascal Bovet, Terrence E. Forrester, Estelle V. Lambert, Dale A. Schoeller, Ramon A. Durazo-Arvizu, David A. Shoham, Guichan Cao, Soren Brage, Ulf Ekelund, Richard S. Cooper, Amy Luke. Accelerometer-measured physical activity is not associated with two-year weight change in African-origin adults from five diverse populations. PeerJ, 2017; 5: e2902 DOI: 10.7717/peerj.2902

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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