Over the last century, both fructose intake and obesity have risen dramatically. With the introduction of high-fructose corn syrup, those numbers have continued to climb. Americans consume 30% more fructose than they did 20 years ago, and 4 times the amount that they did 100 years ago (1). Because this mirrors obesity and diabetes rates, many are wondering if fructose is to blame.

Originally, as fructose hit the scene, it was thought to be the perfect sweetener for diabetics. Because it’s digested differently from glucose, it doesn’t stimulate insulin secretions (2). Although it might not stimulate an immediate response, the research is showing that it might be far worse than glucose. Animal studies show that fructose may increase triglyceride levels more than glucose or sucrose (which is glucose+fructose) (3). The animals in another study that consumed high levels of fructose over a long period of time developed insulin resistance, obesity, type 2 diabetes, and high blood pressure. The results have been less extreme in human studies, but high amounts of fructose appeared to lead to high cholesterol and triglycerides, as well as decreased insulin sensitivity. (4)

There are many theories about ways that fructose could cause obesity and diabetes. It could be that it doesn’t provide the satiety that glucose does, or it could increase uric acid concentrations.  In one study, when uric acid was lowered, participants were able to avoid weight gain, high triglycerides, insulin resistance, and high blood pressure. (5)

While there is evidence that high levels of fructose consumption could be the cause of the rise in obesity, heart disease, and diabetes, there’s not enough evidence to suggest that (at least at moderate levels) it’s dangerous. (4) In other words, it might not just be fructose causing these epidemics, but the amount of sugar in general that we eat.

One of my favorite sayings is, “The dose makes the poison.” At super high levels, most things are bad for us, and that appears to be the case with fructose and all forms of sugar. Please note that I’m not talking about natural sugars that are found in fruit and dairy. We’re not gaining weight from eating too many apples. I’m talking about the added sugar from table sugar, high-fructose corn syrup, honey, etc. that are found in a whopping 74% of packaged foods sold in supermarkets! (6)

The average American consumes about 22 teaspoons (350 calories) of added sugar every day, and about half of that is coming from sweetened beverages likes soda, sport and fruit drinks, teas, and energy drinks. (7) That’s about 3 times the amount recommended by the American Heart Association (9 teaspoons for men and 6 teaspoons for women). Sugar intake at this level has been shown to cause increases in weight, triglycerides, blood pressure, and insulin resistance (5), all of which increase our risk of heart disease and diabetes.

Now you might be thinking, “I already know how bad sugar is…but it’s in everything!” You’re so right. Sugar is added to most of our foods, and because food labels don’t separate added sugar and natural sugars, we can’t rely on food label grams of sugar alone to determine how much of the sugar is added to foods that contain fruit or dairy. For example, the label on chocolate milk says it has 18 grams of sugar, but 12 grams are natural sugar (lactose), which means it has 6 grams of added sugar. So your chocolate milk has less added sugar than 2 tablespoons of ketchup (8 grams). Because of this, I recommend looking for added sugars in the ingredient list and not just the nutrition table. Below are various names (some of them very sneaky) for added sugar (8):

  • anhydrous dextrose
  • brown sugar
  • confectioner’s powdered sugar
  • corn syrup
  • corn syrup solids
  • dextrose
  • fructose
  • high-fructose corn syrup (HFCS)
  • honey
  • invert sugar
  • lactose
  • malt syrup
  • maltose
  • maple syrup
  • molasses
  • nectars (e.g., peach nectar, pear nectar)
  • pancake syrup
  • raw sugar
  • sucrose
  • sugar
  • white granulated sugar

To decrease the amount of sugar in your diet, aim for less processed foods, and check your nutrition tables and ingredients lists. Remember, a little won’t hurt, but too much just might, so instead of having a “spoonful of sugar [to] help the medicine go down,” let’s cut out the added sugars and thus the medicine!

Megan Ostler MS, RDN
iFit Dietitian