You may not realize it, but we’re being poisoned by a common additive present in a wide array of processed foods like soft drinks and salad dressings, store-bought cakes and cookies, snacks, breakfast cereals and breads. I say “poisoned” because this universal additive is increasing our risk of obesity, diabetes, high blood pressure, and atherosclerosis (hardening and narrowing of the arteries).
The additive I’m referring to is high-fructose corn syrup. It is so abundant in refined foods and over-consumed by the average American (often without realizing it) that many experts believe our country will encounter even more obesity and metabolic disease (like diabetes) in the future.
High-fructose corn syrup, which is made from corn, was developed in the 70s as a low-cost sweetener for foods. While regular table sugar (sucrose) is 50% fructose and 50% glucose, high-fructose corn syrup can contain up to 80% fructose and 20% glucose. Glucose is the natural simple sugar found in plant saps and fruit that is sweet that the body can use for energy.
Eating too much of any type is problematic because fructose is metabolized differently from glucose. Fructose is converted to fat in the liver and can be readily stored as body fat. That’s why processed foods are not recommended, and fruit is only recommended in moderation. Of course, fruit is generally healthy, containing vitamins, minerals, and fiber but we are striving for the best possible results, so keep the fruit intake to a minimal amount. To that point, vegetables are a source of these same nutrients because most vegetables do not contain fructose (fruit sugar).
It would be assumed that since fruit is a carbohydrate it would react just like other carbs in the body. However, that is not the case. Nearly all the calories from fruit are in the form of simple sugars, and the majority of these are fructose.
Fructose (fruit sugar) does a few different things in our bodies. First, the fruit sugars can be converted to fat in the liver. It fills the liver with these stored carbs for energy but that means there isn’t room for the “good carbs”. The “good carbs” get pushed out and become stored as fat. The body cannot use the “good carbs” to help in recovery.
In the liver, two things can happen with the fructose. First, fructose can be absorbed by the liver cells, converted to glucose which is important for energy, and then stored as usable energy. Second, the fructose can be converted to fat through an enzyme that operates as a switch to decide if a sugar gets stored as glycogen (usable energy) or converted to fat. Fructose tends to completely bypass this enzyme and is readily converted to fat by the liver. Simply put, a large portion of the fructose simply gets converted directly to fat and released into the bloodstream.
Bam, you get a dose of fat!
The last problem is that fructose cannot be used to replenish muscle glycogen (or energy stored in the muscles). Therefore, on a high fructose diet when the liver gets full, we start converting carbs into fat without thinking about what the muscles need and it becomes a nightmare. Fructose is the worst carb source for exercisers as you can imagine. If you wanted to design a supplement to ruin your physique, it would be a high-fructose-based energy bar. Unfortunately, the vast majority of the “energy” bars out there rely on high-fructose as their major carb source, because it’s cheap.
In summary, fructose does three things: a large portion of it is converted directly to fat by the liver; it preferentially fills liver glycogen stores so that even good carbs are more prone to spill over into fat, and it cannot be used by muscle to recover glycogen. Calorie for calorie, the only nutrient that will make you fatter than fructose is fat itself!