(Image from: MuscleProdigy.com)
Fructose, high fructose corn syrup, fructose corn syrup, fructose, fructose, fructose.
We hear quite a bit about how we should all avoid "fructose", but why is it so dangerous?
Well, this past semester, I had to watch "The Bitter Truth", a lecture given by Dr. Lustig of UCSF, for my nutrition class. Though research on the effects of fructose are continuing, here's what most people believe so far (and what I've been taught):
Origin of fructose in our food:
During the "fat-free" craze during the 80's and 90's, all fat was eliminated from processed goods. Now fat is an essential component for structure, mouthfeel, and most importantly, flavor, so what did the manufacturer's add in to these products in place of fat? Fructose.
Fructose vs. Glucose:
Our body can only absorb/use basic forms of macronutrients. Glucose and fructose are two examples of monosaccharides, the basic, absorbable units of carbohydrates. It's found in foods (starches, fruits) and can be produced by the human body. Glucose is utilized by all body cells to produce our bodies' universal energy source (ATP), so it's very important!
Fructose, on the other hand, can only be metabolized by the liver (there's some people saying that fructose can be metabolized by a few other organs, but the liver is really the main powerhouse that burns up fructose).
Given that glucose can be used by all cells, it's not as dangerous when we eat an excess of glucose. Since fructose can only be metabolized by the liver, however, excess fructose consumption overloads the liver. The liver's storage of carbs (glycogen) has a maximum storage capacity; once this is exceeded, the excess is stored as fat, increasing VLDL levels (very low density lipoprotein; aka "bad" because it's predominantly composed of triglycerides), and increasing cholesterol and triglyceride deposits around organs, a process called "dyslipidemia".
Dangers of fructose:
Dyslipidemia is only the start of health issues linked to excess fructose; dyslipidemia increases the risk for cardiovascular disease. The deposition of fat around the liver may lead to "non-alcoholic fatty liver disease", insulin resistance (which may later lead to Type II diabetes and/or obesity), leptin resistance (a satiety hormone -- resistance would mean that your body doesn't respond when leptin signals that you are full, increasing overeating, disturbing your metabolic balance, and potentially leading to obesity).
Now this doesn't discount the dangers of sugar -- sugar is composed of glucose and fructose. However, sugar isn't as commonly added into processed goods anymore; fructose is! Fructose is made from corn, which is heavily subsidized in the US -- it's cheaper for manufacturers, so fructose is much more prevalent in processed foods (junk foods, soft drinks, medication, baby foods).
Due to its heavy presence in processed foods (which is what most Americans overeat -- either out of choice due to its convenience and/or taste, or, out of necessity because it's cheap!), our bodies can be easily be consistently overloaded with fructose. It's in baby food, for crying out loud! Dr. Lustig even stated in his video that he's seen infants with non-alcoholic fatty liver disease; this early problem leads to a mess of lifelong health issues to follow.
So given all of these dangers, fructose isn't worth adding into your diet. It's fine to enjoy oreos every now and then, but I urge you to really make the effort to eliminate it from your diet as much as possible!