High-fructose corn syrup vs table sugar


High-fructose corn syrup was introduced into our food supply about 40 years ago as a cheap substitute for cane sugar (sucrose). The past 40 years has also seen a dramatic rise in obesity, metabolic syndrome, and type 2 diabetes. Many have come to the conclusion that the two must be related, but many other people (typically from the processed food industry) claim that sugar is sugar and it’s overeating that causes obesity rather than the type of food consumed. While excessive amounts of sugar is definitely a big part of the problem, it is more than just a coincidence that adding high-fructose corn syrup into so many foods we eat accompanied these chromic illnesses. This article will explain the similarities between high-fructose corn syrup and table sugar that keep the debate going, but more importantly, I’ll get into why the two are so different and why high-fructose corn syrup really does cause additional trouble.

Both contain fructose in nearly equal amounts

This is the crux of the argument concerning how the two sugars are basically the same. People get hung up on the “high-fructose” part of the name but in reality high-fructose corn syrup is about 55 percent fructose and 45 percent glucose while table sugar (or sucrose) is exactly 50 percent fructose and 50 percent glucose. The only difference is that the corn syrup is a liquid with the two simple sugars floating in solution while the table sugar is a complex sugar with the two simple sugars chemically bonded in a one-to-one ratio. When you consume table sugar, the sucrose is broken back down into the two simple sugars and released into your system. Advocates of high-fructose corn syrup will tell you that ultimately it’s the same once it’s broken down in your body, but it’s already been established the more simple the sugar, the faster it is released in your bloodstream. Unless you’re running a marathon and need a quick infusion of sugar, these spikes are not good for you. When sugar enters your system at a rapid rate it causes your insulin to spike which makes you more likely to store consumed fat, less likely to release fat from fat cells, and it will cause your appetite to surge again in a relatively short time causing you to overeat.

The starch in a potato is also a complex sugar. It’s basically just a long string of glucose molecules. By the food industry’s logic then potatoes should be as high a contributor to obesity as table sugar or high-fructose corn syrup, but the history of this staple food product does not support that. Yes, potatoes are also high on the glycemic index, but centuries of evidence do not show them to be a huge contributor to obesity and other health problems. It’s almost as if a sugar is not a sugar, even though ultimately they all get broken down to simple sugars in our bodies.


We don’t process fructose the same

Another problem with high-fructose corn syrup is the fact that we don’t process fructose as we do with glucose. Glucose is processed in the liver into glycogen (if needed) where it can then be stored in the liver or in muscle cells. We refer to glucose as blood sugar because it can also be processed by other cells for fuel with the help of insulin. Fructose, however, is only processed in the liver. If the liver already has plenty of stored glycogen (which it does in pretty much everyone in our well-fed society), then any excess sugar gets immediately turned into triglycerides (fats) which are then deposited in fat cells or in the liver itself causing fatty liver disease. Fructose does not cause a rise in insulin and unless you’re glycogen-depleted, it will most likely be processed into body fat.

A recent mouse study in Scientific Reports highlights the impact fructose can have on your body, even when the total calories consumed should not have led to weight gain.

Two groups of mice were given a daily calorie allotment that would maintain a healthy weight. One group of mice received 18 percent of their daily calories from glucose and the test group received 18 percent of their calories from fructose. Why 18 percent? Because while fructose accounts for about 10 percent of daily calories consumed by the average American, the average adolescent actually gets about 15 to 23 percent of their daily calories from fructose (boys are typically the ones on the higher side of the range).

What the study found was that even though the two groups were matched calorie for calorie and should not have been gaining weight, the fructose group did gain body fat throughout the study. They also found that the mice fed fructose had significantly fattier livers (which contributes to all kinds of health issues) and they moved less than the control group. They’re not really sure why the fructose group moved less but they concluded that was one reason for the unexpected weight gain. They also theorized that since fructose is metabolized differently than glucose, this also may have contributed to additional fat deposits. My personal theory is that if your consumed fuel is being turned into body fat instead of being used as immediate fuel for your muscles, you will be much less inclined to move. This is comparing pure fructose to pure glucose, the real test comes when we look at high-fructose corn syrup verses table sugar.

We don’t process the fructose in table sugar like we do in high-fructose corn syrup

Another mouse study from Princeton University had a similar set up. Two groups of mice were fed calorically-identical diets, but one group was fed high-fructose corn syrup (the equivalent of half a can of soda per day) while the other group was fed table sugar (the equivalent of a full can of soda per day). Predictably, every mouse in the high-fructose corn syrup group gained much more body fat (especially around the abdomen) and had higher triglyceride levels in their blood stream, all signs of metabolic syndrome. Even the researchers were surprised by how different the results were between the two groups. Yes, our bodies ultimately break the table sugar into the same fructose and glucose molecules, but the additional metabolic step required does seem to help lesson the impact.

Free-floating glucose doesn’t help either

So if fructose doesn’t raise insulin, then why does high-fructose corn syrup cause insulin spikes and the corresponding surge in appetite later? That’s where the glucose comes in. High-fructose corn syrup is still 45 percent glucose, and having this free-floating simple sugar flood into your system causes all kinds of problems as well. Remember, the faster sugar is introduced into your blood stream, the more problems it will cause. It doesn’t take much metabolic effort for your body to break down sucrose, but it’s just slow enough to make a difference.


Does this mean fruit is bad?

This question inevitably comes up when people hear about the negatives of fructose. As I mentioned in a previous article, not only is the fructose in whole fruit not harmful, but it’s almost like free calories as far as your body is concerned. Processed food contains incredibly concentrated amounts of fructose at levels that you can’t find in nature. Not only that, but a great deal of the sugar is further locked away behind indigestible fiber that causes it to be released into your bloodstream at a slow and manageable rate.


Added sugar in general is bad

The food industry is right about one thing, a huge contributor to obesity is the immense amount of sugar they put in everything. Have you ever wondered why absolutely everything from ketchup to sausage to bread as tons of sugar in it? It’s actually not for taste although that is a pleasant side effect. Sugar is a natural preservative because it absorbs water. Do you have a jar or container with table sugar in it? You’ll notice you can leave it open indefinitely and it never goes bad. In more humid areas it may clump, but it never spoils. It does this by drawing the moisture out of any bacterial cell that come near it. For the food industry it’s a win-win. Lots of sugar means great tasting products that stay moist and fresh for a longer period of time on the store shelves. All that sugar is not for your benefit, the food industry does it to prevent food from spoiling on the shelves. Everyone is so obsessed about artificial preservatives that they missed the fact the natural ones are actually killing them. One mouse study from the University of Utah actually demonstrated how high-fructose corn syrup shortened the lifespans of female mice. Sugar is not evil and does not need to be avoided completely, but to change your life, you really do need to cut down the percentage of how much you consume each day.

David G

Interesting article, Chris. Are you a doctor, dietician, or some other sort of nutrition professional? It would benefit me, and other readers I’m sure, to include a brief author bio like most other blogs do. It would include your full name, and list the relevant training you have in order to offer the information and opinion in your posts.

I like your posts, but often ask myself why should I care what this guy says? Everyone has an opinion, etc. if you have some relevant training, including it in a brief bio will add some credibility to your posts.

Thanks in advance!


Chris K

We did have my bio on here before but I guess we lost the place for it when we reformatted the blog. We’ll figure out a place to put it back up. The short version is I’m an NASM Certified Personal Trainer, a black belt in Jiu Jitsu, and I have an MBA from the University of Utah. My health education is more informal than official, but I’ve been studying nutrition and fitness for about 20 years at this point. I credit a great deal of my knowledge and understanding of how to properly read research to Bryan Haycock. He is a professor at the University of Utah that I worked with at another fitness company for 5 years. I was basically fortunate enough to receive a free health and nutrition education 8 hours a day, and it really refined the way I determine the veracity of the information I find. I’ve also trained hundreds of people in Jiu Jitsu, weight loss, and strength and conditioning over the past 20 years, so I feel I also have a good mixture of applied experience to qualify my opinions.

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