What’s the Story About Fructose?

In April, 2012 CBS’s 60 Minutes broadcast a piece on the “toxicity” of sugar during which Dr. Robert Lustig, a pediatric endocrinologist, was interviewed. Specifically fructose, a particular form of sugar, was targeted. We have been hearing for some time that high-fructose corn syrup (HFCS) may not be good for us. Yet, fructose is in fruit, which we understand to be healthy…so what is the right answer?

A few months before this broadcast, I had the opportunity to hear Dr. Lustig speak during the American Society of Bariatric Physicians course on Obesity and Associated Conditions. Much of his presentation was focused on the complex metabolic physiology of fructose and its role in type 2 diabetes, obesity, and cardiovascular disease. As a physician with a passion for helping patients identify and reverse the medical problems that accompany unhealthy adipose (fat) tissue, I paid close attention.

Fructose constitutes approximately half of the sugar content in high-fructose corn syrup. Many people are surprised, however, to find out that it constitutes about half of the sugar content in sucrose (table sugar) as well. HFCS and sucrose are added to a wide variety of processed foods and all this sugar must be metabolized by the liver. The main trouble with fructose, specifically, is that it is mostly converted into fat. Fructose is rapidly stored in fat cells, and results in more fat production than other types of sugar. Consequently, even if what you eat says “low-fat” on the label, if it contains HFCS or sucrose, it won’t remain that way once it is processed by your liver. Once you start checking, you may be surprised where you find it: kid cereals, ketchup, and even baby formula. So read labels carefully and choose foods that don’t have added HFCS.

Your liver is designed to manage a moderate amount of fructose without issue. However, in the levels most Americans consume today, it is likely leading to unhealthy consequences and weight gain. Fruit also contains fructose, which could similarly affect some who are struggling with metabolic and adipose tissue problems. When discussing healthy eating, we often hear “fruits and vegetables” mentioned together, as if they were equally beneficial. However, this isn’t really the case for most of my patients. That being said, for most of us, it is the *added* sugars in the diet which are the biggest offenders…not the amount of fruit we’re eating. And, if you are going to eat a dessert, then certainly it is better to have a piece of fruit, rather than some chocolate cake or a candy bar.

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