Does High Fructose Corn Syrup Really Make You Fat?

October 1st, 2013 by

High fructose corn syrup has come under fire in recent years due to suggestions that it causes everything from obesity to Diabetes.  Today I wanted to take a quick look at HFCS, what it is, and what the research says about its potential dangers and side effects.

What is High Fructose Corn Syrup

High fructose corn syrup is basically a liquid solution consisting of both glucose and fructose in which the molecules float around separate from one another rather than being attached to one another as they are in sucrose (table sugar).  In table sugar both glucose and fructose are present in equal amounts (50% glucose and 50% fructose).  With HFCS the relative amount of fructose generally ranges between 42-55% (although higher concentrations do exist for use in hard candies).

But ultimately the most major difference is that there is about 5% more fructose in HFCS than there is in table sugar.  It is primarily used because it is inexpensive and confers a greater amount of sweetness than a similar dose of sucrose.

Will HFCS Make You Gain More Fat Than Sucrose?

Well…so far the largest reviews of research in this area suggest that this isn’t the case.  It appears that when fructose is replaced with equal (isocaloric) quantities of sucrose there is no difference.  It appears that calories, more than the source of the sugars, are most important in determining fat gain.

From a review and meta-analysis by Sievenpiper et al:

“In conclusion, aggregate data analyses of controlled feeding trials do not support a body weight–increasing effect of fructose in isocaloric exchange for other sources of carbohydrate in the diet. However, evidence indicates that added fructose providing excess energy at extreme levels of intake may have a body weight–increasing effect over the short term, although confounding from excess energy cannot be excluded.”

But What About Triglycerides?  Or Diabetes?  Will it Mess With My Insulin?

Again, it seems that there is little difference between sucrose and HFCS.

From a review by Dolan et al:

“In conclusion, the present review shows that intake of normal amounts of fructose has the same effect on TG or body weight in overweight or obese individuals as similar amounts of other carbohydrates such as glucose or sucrose. […] Studies that have shown adverse effects of fructose on these variables have been performed with abnormal levels of intake…”

And from a review by Rizkalla:

“Certainly high fructose consumption can induce insulin resistance, impaired glucose tolerance, hyperinsulinemia, hypertriglyceridemia, and hypertension in animal models. There is no evidence for similar effects in humans at realistic consumption patterns. […] A moderate dose (≤ 50g/day) of added fructose has no deleterious effect on fasting and postprandial triglycerides, glucose control and insulin resistance.”

But What About  THIS STUDY That Showed Fructose Increases Uric Acid in Humans?

That certainly shows the potential harm of fructose, but again, the dose there was 150g per day which is pretty darn high.  Given that most sodas use about 10g HFCS per 100 ml, that would mean a single can of soda would have about 33.5g fructose.

So you’d be into your fifth can of the day before you hit this amount of HFCS.  I think we can all agree that 5 cans of soda per day is probably going to have negative consequences regardless of whether sucrose or HFCS is used.

Going back to the previous review by Rizkalla, 50g or less per day really doesn’t seem to have any adverse effects.  As with most things, it appears that moderate consumption isn’t particularly harmful.  It is when we get into a state of excess that it becomes problematic.

 But All These Studies Are Funded By The Industry So They Are Biased

I’ll be the first to say that studies should always be evaluated first based on their merits, but if you’re concerned about the industry having total control, here are some statistics on the funding from the Sievenpiper review.

  • 10% funded by industry alone.
  • 34% funded by a single agency.
  • 55% funded by a combination of agencies (government, university, non-profit organizations)

While industry does have SOME influence, in this case it certainly isn’t very much.

The Wrap on High Fructose Corn Syrup

In the end, it seems that quantity more than anything is the primary factor in the “dangers” of HFCS.  As with normal table sugar, consumption in moderation appears to be okay but consumption of large quantities can have consequences for weight gain and health.  And weight gain, for the most part, will be dictated by the overall calories consumed.

It is time to put the internet fear-mongering to bed.