04 Jun Fructose Linked To Weight Gain and Reduced Physical Activity
Medical Research: What is the background for this study? What are the main findings?
Dr. Rendeiro: The motivation for this study emerges in the context of understanding the link between sugar intake, particularly fructose, and the rising obesity epidemic that we are currently facing. Overeating and lack of physical activity certainly play major roles in obesity, but the sources of calories are also important. Fructose, a simple monosaccharide found in fruit and vegetables, and composing half of sucrose (i.e., table sugar), has been on the increase in Western diets. In our rodent study, 18% of dietary calories were derived from sugar, either fructose or glucose. This level is similar to typical American diets. However, the fructose diet resulted in increased weight gain and fat deposition and reduced physical activity even though food intake was similar between the two groups. It is also important to note that our animals were consuming their regular amount of calories, not overeating. Only the source of sugar was different between experimental groups, and still calorie-for-calorie, fructose caused greater weight gain and less physical activity than glucose.
Medical Research: What should clinicians and patients take away from your report?
Dr. Rendeiro: First of all, it is important to restate that the consumption of added sugars through soft drinks and other processed foods should be kept to a minimum in our diets, regardless of the type of sugar. The American Heart Association recommends a maximum of 5% daily calories derived from added sugars, but in the US, intake of added sugar can reach three to four times that recommendation.
Our study further suggests that at those unhealthy levels of sugar intake (18% of dietary calories derived from sugar), consuming fructose results in more fat accumulation, weight gain and physical inactivity. If the goal is to promote weight loss and physical activity, it could be useful to consider minimizing the amount of food with added fructose that is consumed. In the end, consuming a calorically-appropriate diet, including fresh fruits and vegetables, and maintaining an active lifestyle are extremely important.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Rendeiro: Future work should examine the extent to which fructose, calorie-for-calorie, may impact neurological function as compared to glucose. In our study, we did not find any differences in the brain or behavior outcomes as a result of fructose intake, but we only investigated the growth of new neurons and performance on a few learning and memory tasks. We also only supplemented the animals with fructose for 10 weeks, so it is possible that any potential negative effects in brain function might emerge after longer exposures to fructose.
Catarina Rendeiro, Ashley M. Masnik, Jonathan G. Mun, Kristy Du, Diana Clark, Ryan N. Dilger, Anna C. Dilger, Justin S. Rhodes. Fructose decreases physical activity and increases body fat without affecting hippocampal neurogenesis and learning relative to an isocaloric glucose diet. Scientific Reports, 2015; 5: 9589 DOI: 10.1038/srep09589
MedicalResearch.com Interview with: Catarina Rendeiro Ph.D., Post-doctoral Research Associate, Rhodes lab University of Illinois, & Urbana, Illinois (2015). Fructose Linked To Weight Gain and Reduced Physical Activity MedicalResearch.com