A diet high in fructose causes obesity in rats. This was the conclusion of a new study completed in August at the University of Florida. Increasingly, there have been suspicions that the high fructose corn syrup (HFCS) that is found
A diet high in fructose causes obesity in rats. This was the conclusion of a new study completed in August at the University of Florida. Increasingly, there have been suspicions that the high fructose corn syrup (HFCS) that is found in almost all processed food in America has played a role in the epidemic of obesity. The suspicion has been due in part to the fact that our obesity epidemic picked up great speed in the early 1970s and this was just after HFCS was added to the American diet. Americans have become the most obese people on the planet. This obesity has increased by 60 percent in just the past 20 years. Obesity in childhood has tripled.
In the past, the suspicions concerning HFCS have been countered by arguments that there have been no good studies proving the link between fructose and obesity. This new study is unique in that it appears to be the first to show a direct link. What it showed is that rats fed a high fructose diet became resistant to leptin and leptin is a vital hormone which regulates eating. When species are resistant to leptin, they eat much more food.
A groups of rats was placed on a high fructose diet and a control group was placed on a no fructose diet. After six months, both groups were switched to a high calorie, high fat meal plan (similar to our western diet). The high fructose diet rats became substantially fatter. Additional studies were done also which showed that these high fructose rats were now resistant to the hormone leptin and they ate, as predicted, much more of the offered food.
High fructose corn syrup is the leading sweetener in America today. It is a 4.5 billion dollar industry and it is estimated that the average American consumes about 62 pounds a year of this form of fructose. (Try a little experiment; look on the label of almost any processed food. You will almost always find HFCS.)
There are obviously still many questions to be answered. The studies will need to be repeated in humans. We also need to better understand possible differences between HFCS and regular table sugar which also contains fructose. A big remaining question is whether we can regain our sensitivity to leptin by stopping the consumption of HFCS.
My predictions are that we will conclusively prove that the HFCS found in most American processed foods is a major cause of our obesity epidemic. It will become the trans fat of the future.
In the meantime, I would try hard to not eat processed food. Shop around the border of the grocery stores where you can find real fruits, vegetables and meats and even better go to the sunshine markets and buy locally grown food. Most importantly, stay away from soft drinks. They may contain up to 10 teaspoons of sweetener (usually HFCS) per can. I think we will also be finding out that the diet sodas have their own set of problems but that is another article.
• Dr. Lee Evslin has been a physician on Kaua‘i for 30 years and has a special interest in nutrition.
