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Functional Medicine

And You Thought Fructose Was Safe

By July 27, 2021August 10th, 2021No Comments

There’s a video on Youtube of an endocrinologist named Dr. Robert Lustig speaking at length about the evils of fructose and for an educational video, it’s impressively gotten over 13 million hits! You might be surprised so many people would be interested, but he explains quite clearly to his audience why the overload of fructose is so very damaging to our bodies.

And back in April, Gary Taubes wrote at length about the same thing in a New York Times article called “Is Sugar Toxic?”.  Both of these sources are highly recommended and fascinating — click on the links.

Now, I’m not saying to NOT eat that orange or apple, since most of us know fructose is fruit sugar. But most people have way too much fructose in their diet.

Just a couple of quick points so you know what’s what:

  • Sucrose (white table sugar) is made up of a 50-50 split of fructose and glucose
  • High fructose corn syrup (HFCS) is a 55-45 split of fructose and glucose (not much difference, right?)
  • Fructose does not metabolize the same way as glucose does -—it goes directly to the liver. That’s why it’s called “low-glycemic” — because it doesn’t cause an insulin spike. That doesn’t mean it’s safe, though.
  • Fructose is the main cause of non-alcoholic fatty liver disease these days, with 20% of obese children having the disease, with cases being diagnosed in toddlers.
  • Fatty liver disease accelerates your chances of getting insulin resistance, diabetes and heart disease.
  • Fatty liver disease is the step before liver cirrhosis (scar tissue in the liver and then, over time, liver failure).

Here’s a mind-blowing fact:


“But I thought fruit was healthy!” lots of people say to us! Yes, in moderation, but “fruitsandvegetables” is not one word; they are not the same thing. You can’t substitute fruit for vegetables all the time. Yes, fruit is better than, say, a Pop-tart, but that doesn’t mean you’re in the clear to eat fruits 3 times a day, or even once a day.

Weight Watchers made a huge change back in 2010, by overhauling their whole point system because they finally realized that a calorie is NOT just a calorie, and that the source of the calorie counts. But one thing that will come back to haunt them is that they made fruit “free” — you can eat as much as you want. We’ve seen several patients who had been doing Weight Watchers and couldn’t understand why they weren’t losing weight until we explained this whole thing about fructose.

Nature designed it so that we couldn’t overeat fructose, by putting it with fiber. Take an orange, for example. You’d probably be full after one. So what do people do? They take 6 of them and juice them, removing all the fiber and concentrating the fructose, giving you essentially a high fructose product. All fruit juices, organic or not, are still high fructose products and should be consumed in moderation, if at all. In fact, the American Pediatric Association recommends severely limiting fruit juice consumption in children (no more than one glass per day).

And remember — we used to actually eat fruit seasonally. But now we can get fruit from all over the world year-round — strawberries in December, apples in June, oranges in July — and without the natural limitation of the seasons, we eat and eat.

So where do you find high concentrations of fructose? In eating too much fruit, obviously, and then also in sodas, with their high fructose corn syrup. Sugar, being 50% fructose, is a big offender. Agave nectar is another one — advertised as “low-glycemic”, it’s actually higher in fructose than HFCS at an eye-popping 90%. Low-fat foods often have sweeteners in them, some of them being HFCS. There’s a new thing popping up on sodas — crystalline fructose. Don’t fall for it. Just read the labels.

How much is too much? Some people notice they can’t lose weight if they eat too much fruit. Personally, we eat fruit maybe twice a week, perhaps a little more in the summer. We see other sources saying that for adults, keep fructose sources to less than 25 grams per day, and for kids even less — like 15 grams a day (because they often will get more from other sources, since it’s added to just about ALL processed foods and beverages. We try to buy seasonally and we try to buy local.

We’re not saying that fruit itself is bad, but we ARE saying that concentrated fructose sources will cause huge amounts of damage, from weight gain, to insulin resistance, to liver problems. Everything in moderation!

Author Dr. Marlene Merritt, DOM, MS, CNS

• Doctor of Oriental Medicine • Certified Nutrition Specialist • Institute for Functional Medicine Certified Practitioner • Bredesen Certified in Cognitive Decline • Shoemaker Proficient in Treating Mold Illness

More posts by Dr. Marlene Merritt, DOM, MS, CNS