Blame it on the Sugar?

Last Spring, the CBS television program 60 Minutes aired a story titled Is Sugar Toxic? Dr. Robert Lustig, a pediatric endocrinologist at the University of California-San Francisco, argues that the consumption of fructose is the cause of increased rates of obesity, type 2 diabetes, heart disease, and metabolic syndrome that have occurred over the last thirty years. In 2009, Lustig gave a lecture called Sugar: The Bitter Truth that has since been viewed by more than 2.6 million people on YouTube in which he gives his reasons for calling fructose poisonous. His lecture, which you can access by clicking here, is quite academic and perhaps a bit esoteric if you have not studied organic chemistry or biochemistry. However, you can find the crux of his argument in the 60 Minutes piece below.

You may be wondering at this point what you are eating that contains fructose. The short answer is that if you have adopted the so-called Western diet, it’s in everything! Table sugar (sucrose) is actually a disaccharide composed of two simple sugars – glucose and fructose. If you put a few scoops of sugar in your iced tea or down a couple cans of soda, you are consuming fructose. Check the labels on most of the processed foods you purchase at the supermarket and see if they contain the ingredient high fructose corn syrup.  Fructose and high fructose corn syrup are found in almost all the foods we eat including cereals, breads, soft drinks, chips, and even peanut butter. Do you put chocolate syrup on ice cream? Double whammy. The real problem is not that we are consuming fructose; rather, it is that we are consuming processed fructose that lacks fiber. To be clear, fructose occurs naturally and you consume it if you eat any type of fruit. However, fruit is replete with high amounts of fiber that protect your body against the harmful of effects of fructose.

Ok, so what’s the big deal? Why is processed fructose that lacks fiber so bad? The answer, according to Lustig and University of California-Davis researcher Dr. Kinder Stanhope, has to do with the liver. When you consume glucose, your liver can convert it into glycogen, which can be used for energy at a later time. Fructose, in contrast, gets turned into fat and some of that fat is in the form of LDL cholesterol. If you are confused by the difference between HDL and LDL cholesterol, an easy mnemonic is to think of the “H” in HDL as standing for “healthy” and the “L” in LDL as standing for “lethal.” LDL cholesterol is associated with increased atherosclerosis (hardening of the arteries) and risk for heart attack. You can read the article published by Dr. Stanhope and her colleagues reporting the findings from their study by clicking here. In short, consuming processed foods that contain high fructose corn syrup is tantamount to eating foods high in saturated fats.

In addition, sugar may actually be addictive. That’s right! What you nonchalantly called a sweet tooth may actually turn out to be a full-blown addiction to sugar. In 2010, Dr. Eric Stice and his colleagues published an article in Behavioral Neurobiology of Eating Disorder that explained how the consumption of sugar causes the reward region of the brain to release dopamine. Whenever dopamine is released, it makes us feel good. The first time you take a bite of chocolate cake, your brain releases dopamine and you feel terrific. However, if you want that same sensation again the next day, you have to eat even more chocolate cake because you build up a tolerance for sugar much like a drug addict. Consuming more chocolate cake means you are consuming more sugar (fructose), which means you are storing more fat and increasing your LDL cholesterol, which means BAM! We have a serious health crisis on our hands. With strong scientific evidence suggesting fructose is toxic and addictive, it’s no surprise that we have seen rates of obesity, type 2 diabetes, heart disease, and metabolic syndrome skyrocket.

What can you eat and drink if fructose is so ubiquitous and yet so harmful? The short answer is that you should avoid processed foods. Eat whole grain bread instead of white or wheat bread. Eat oatmeal or shredded wheat instead of sugary cereals. Put down the glass of apple juice and bite into an apple. Substitute natural peanut butter for classic Jif and Skippy peanut butter. Drink water instead of soda. Making these small but substantive changes will have a long-term positive effect on your health.


So, what do you think? Is sugar to blame for the obesity epidemic and our subsequent health crisis?