Sugar, Sugar

Reducing fructose intake quickly delivers positive metabolic effects, JAOA study finds

Researchers find it’s not the fat, it’s the sugar. Improvements in metabolic measures occur in as little as nine days of fructose restriction.


Researchers have found that the negative metabolic effects of  fructose, a simple sugar, can be reversed when people limit their intake for as little as nine days. The review study “Conversion of Sugar to Fat: Is Hepatic de Novo Lipogenesis Leading to Metabolic Syndrome and Associated Chronic Diseases?”  is published in the August edition of The Journal of the American Osteopathic Association.

Fructose restriction in children with obesity resulted in improved glucose and lipid metabolism, as well as lower liver fat, nine days after the dietary change.

The JAOA review identified fructose as the most damaging type of sugar. Compared to glucose, which metabolizes 20 percent in the liver and 80 percent throughout the rest of the body, fructose is 90 percent metabolized in the liver and converts to fat up to 18.9 times faster than glucose.

Overfed and undernourished

High fructose corn syrup (HFCS) is found in 75 percent of packaged foods and drinks, mainly because it is cheaper and 20 percent sweeter than raw sugar.  The researchers noted that HFCS is particularly harmful because it contributes no nutrients but depletes energy in order to metabolize it.

Fructose is almost immediately converted to fat and stored in the body, adding weight. At the same time, the brain thinks the body is starving and becomes lethargic and less inclined to exercise.

Fighting back

The study notes that once people have put on a significant amount of weight and developed eating habits that rely on packaged foods with HFCS, change can be daunting. Historically, physicians have told patients to restructure their diet and start exercising heavily, with a plan to check back after a month or more. That approach typically resulted in poor patient adherence.

Researchers suggest that focusing the conversation on health instead of weight, with more frequent contact, may be more effective. Improved metabolic measures from fructose restriction can provide an early marker of improved health, even if no weight is lost.

“That single change in diet improves metabolic results in less than two weeks. Imagine the power of doing a ‘before and after’ comparison with a patient, so they can see for themselves that their health is improving. Getting those results, instead of just stepping on a scale, can motivate them to keep going,”  said Tyree Winters, DO, a pediatrician focused on childhood obesity.


  1. M. Shook

    This is somewhat accurate. However, once again, HFCS is being blamed when it isn’t really the true culprit. Yes, anyone with a basic background in biochemistry knows that fructose is more likely to become fat than the other sugars. However, the fructose/glucose ratio in HFCS isn’t that much more significant for most people than that of sucrose (table sugar) or even honey. For HFCS, it is 55%/42%. Sucrose is a disaccharide consisting of a 1 to 1 ratio of fructose and glucose. Some have argued, incorrectly, that being in a disaccharide form makes them less likely to be fully absorbed in the small intestine. However, our bodies can easily break the glycosidic bonds. In fact, sucrase is so efficient that virtually no sucrose makes it to the colon. Honey’s sugar profile is more varied. It consists of about 38% fructose, 31% glucose, 7% maltose, 1% sucrose, and 1.5% maltodextrin (studies have shown that it’s metabolic effects are similar to sucrose). Since maltose is broken down into two glucose molecules, the fructose and glucose ratio of honey is basically the same as that of sucrose. Unless we are taking in extremely large amounts of HFCS of HFC90 (that’s a whole different ballgame as it is 90% fructose), the difference between the mentioned sugars is not our biggest worry. Added sugars, of any kind, are truly to blame. In addition, processed starches have become a significant portion of those which are available. These are less likely to make it to the colon. Resistant starches have significant health benefits because they nourish our colonic gut bacteria. In particular, the polysaccharides are digested into simple sugars by bacteria called Bacteroidetes. Simple sugars produced before the colon are almost completely absorbed. A separate population of colonic bacteria called Firmicutes ferment simple sugars and produce short chain fatty acids (SCFA’s) which nourish the colon. When there is a lack of simple sugars in the colon, Firmicutes eat the mucosal lining of our colon. We do not want this to happen. Changing our diet from simple sugars to more resistant starches nourishes our gut bacteria which leads to a lower likelihood of developing colon cancer as well as obesity. The implications for both of these are obvious.

    1. Aviva Harris

      Very helpful! Thanks so much for taking the time to writing a detailed comment. I will look into adding resistant starches to my meals – and lowering the amount of fruit that I eat.

      1. M. Shook

        I am so glad that you enjoyed my post. Making these simple changes in my diet made a huge difference for me. I no longer carry the extra 25 pounds that were gained since high school. In fact, I can wear the same clothes that I did then, and I didn’t have to get a gym membership to do it. Plus, I have so much more energy. I hope you find the same satisfaction.

  2. Pingback: NEWS: Nine days fructose-free could transform your health

  3. jana knejp

    …I eat enormous amount of fruits… does it mean that I have to limit the fruit (fructose) … or are we strictly talking just ADDED fructose…

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