For over 20 years, efforts to stop or reverse soaring rates of obesity in the United States have failed. In fact, the obesity epidemic is now a global issue. My colleagues and I hypothesized that the increasing prevalence of fructose in our collective diets is not only a major contributor to the obesity epidemic but also responsible for the dysmetabolic effects that result in metabolic syndrome and chronic diseases.
The Dangers of Fructose
We conducted a review, published in The Journal of the American Osteopathic Association, to better understand the role of fructose in these conditions. Along with co-investigators from the University of California, San Francisco, we identified fructose—especially high-fructose corn syrup (HFCS)—as the most damaging type of sugar. Compared with glucose, which metabolizes 20% in the liver and 80% throughout the rest of the body, fructose metabolizes 90% in the liver and converts to fat up to 18.9 times faster than glucose.
We learned that HFCS is found in 75% of packaged foods and drinks, mainly because it is cheaper and 20% sweeter than raw sugar. It is particularly harmful because it depletes energy in order to be metabolized, without contributing any nutrients. Because fructose in its processed form has no nutritional value and isn’t metabolized in the brain, the body and mind don’t register that food has been taken in. Thus, one can consume as much fructose as they want but will always want more.
A Look at Fructose Restriction
Included in our review was a study that sought to determine the metabolic impact of fructose restriction irrespective of weight change. Participants were children with obesity and metabolic syndrome. During the study they consumed a diet to deliver comparable percentages of protein, fat, and carbohydrates as their self-reported diet; however, dietary sugar was reduced from 28% to 10% and substituted with starch. Participants recorded daily weights and underwent dual-energy x-ray absorptiometry scanning, oral glucose tolerance testing, and biochemical analysis.
In only 9 days, isocaloric fructose restriction improved surrogate metabolic parameters, including lipids, glucose tolerance, systolic blood pressure, and metabolic syndrome. What makes these findings so exciting and so important is that even a small change, for just a little more than a week, had a big impact.
The treatment of obesity and its related complications often appear to be overwhelming for both the patient and health care provider. Historically, physicians have told patients to entirely restructure their diet and start exercising heavily, with a plan to check back after at least a month. This has also typically been faced with poor patient adherence.
However, after 9 days of a small adjustment to diet, clinicians can show patients their blood work and say, “Look, you are significantly healthier already.” This approach of focusing on finding health rather than losing weight may give both providers and patients an early success story and a foundation to build upon for further success in dealing with obesity and all that is associated with it.
The Importance of Patient Education
That said, obesity itself is still a serious problem, and a healthier diet coupled with exercise is usually the best way to drop pounds. Helping patients stay the course and not become complacent after the initial success is still a challenge.
This is true even when patients attain their desired weight. Physicians have to educate and help manage their expectations. Most patients who successfully lose weight put it back on within a few months, which can be very discouraging. Clinicians should explain to such patients that their bodies have become accustomed to maintaining a certain amount of fat reserve and want to keep that regardless of current conditions. They have to understand that it may be 1 or 2 years before their body adjusts to a new level of fat storage and will more easily maintain a lower weight.
In the meantime, clinicians can continue to encourage overweight and obese patients that reducing sugar has made a significant difference in achieving their goals of being healthier. We also must push forward on research to better understand how fructose creates both obesity and its dysmetabolic sequelae and identify an approach that will reverse the trend of obesity around the globe.
Readings & Resources (click to view)
Schwarz J, Clearfield M, Mulligan K. Conversion of sugar to fat: is hepatic de novo lipogenesis leading to metabolic syndrome and associated chronic diseases? J Am Osteopath Assoc. 2017;117:520-527. Available at http://jaoa.org/article.aspx?articleid=2646761.
Sanders T. How important is the relative balance of fat and carbohydrate as sources of energy in relation to health? Proc Nutr Soc. 2016;75:147-153.
Kearns C, Schmidt L, Glantz S. Sugar industry and coronary heart disease research: a historical analysis of internal industry documents. JAMA Intern Med. 2016;176:1680-1685.
Schwarz J, Noworolski S, Wen M, et al. Effect of a high-fructose weight-maintaining diet on lipogenesis and liver fat. J Clin Endocrinol Metab. 2015;100:2434-2442.
Lustig R, Mulligan K, Noworolski S, et al. Isocaloric fructose restriction and metabolic improvement in children with obesity and metabolic syndrome. Obesity. 2016; 24:453-460.