Why is Sugar Poisonous? The “sciencey” part
Warning: this is a long post but I hope you read it and that it makes some sense.
In a previous post I introduced you to the video by Dr. Robert H. Lustig that walks you through why sugar is poison and how it is contributing to the obesity epidemic. Today I’m going to tackle the science and try to break it down into something more understandable. I do not presume to understand all the science that Dr. Lustig spouts but I get the gist of it. Let’s hope I do a credible job of splainin it to ya’ll. Please remember that this is about why sugar is considered a poison and how it makes us fat. Other than the brief discussion about insulin resistance, this isn’t about diabetes, per se. However, those of us who have T2 need to attempt to keep our weight down in order to help control our glucose. Increased weight increases insulin resistance. So here is my very simplified version:
Glucose is the “energy of life”. Glucose is what our bodies are intended to use for energy. Glucose is consumed through the foods we eat and is either burned as fuel or stored in the liver for later use.
Let’s look at how the body processes glucose, ethanol, and sucrose (sugar) which is 40% glucose and 60% fructose. In all cases, the liver does some of the processing.
Glucose: If we ate 2 slices of white bread (120 calories) this is how it would be processed in our bodies: 80% will be used by the body immediately because “glucose is the energy of life”. The other 20% hits the liver (24 calories). During the processing, glucose 6 phosphate stays in the liver and becomes fat, but it’s not a lot (remember, only 24 calories). It becomes glycogen which is the storage form of glucose in the liver. How much glycogen can your liver store before it gets sick? Any amount….unlimited. Glycogen is a non-toxic form of glucose in the liver, therefore you can have LOTS of it and your liver will not go into failure. The whole point of consuming glucose is to restore the glycogen reserves in your liver. What doesn’t get “burned off” during the processing of glucose becomes fat or VLDL which causes heart disease so we don’t want much of that in our system. We started out with 24 calories and maybe ½ a calorie becomes VLDL. Because insulin was triggered when the bread was eaten, it tells the brain, via leptin, that you ate something and should be getting full.
Ethanol (alcohol) is a carbohydrate and it’s a toxin. The brain metabolizes ethanol, that’s why your head gets fuzzy when you drink. Your brain is telling you, “Hey, you’ve had enough!” Now if we can just learn to listen to our brains…. Ethanol is an acute toxin and we know that. We control ethanol, ie: age limits and taxes etc. to limit the consumption of alcohol. When we ate 2 slices of white bread, 24 calories of glucose hit the liver. When we drink a shot of alcohol (same 120 calories as the bread), 96 calories of alcohol hits the liver or 4 times the calories. Some of the ethanol converts to acidaldehyde which, if enough is present, will cause cirrhosis. During all the complicated processing of ethanol, some is turned into citrate and citrate will turn to fat. The liver pushes out as much citrate as it can because a fatty liver is bad. It’s pushed out as VLDL, just like it did with the .5 calories from glucose. There are LOTS more calories from alcohol that convert to VLDL as opposed to what comes from glucose because 4x as much went into the liver in the first place. (I wish he would say exactly how many calories, but he doesn’t.)
Now let’s consume 120 calories of sucrose (a glass of orange juice). Sugar (sucrose) is 60% fructose and 40% glucose. We’ve already seen above how the body handles the glucose so let’s look at the fructose. 100% of the fructose will be metabolized by the liver because ONLY the liver can metabolize fructose. No insulin is triggered when fructose is consumed, therefore, none of it is transported to the cells for energy. So we have 72 calories that need to be processed by the liver as opposed to 24 with glucose (white bread). That is three times as much. The processing of fructose in the liver is tons more complicated than when processing glucose and this is where the science gets deep. Simplified: 3 times as many calories need to be processed; some goes here, some goes there and none of it is good. One of the by-products is uric acid which can lead to gout. Uric acid also increases blood pressure. There is lots of citrate produced that binds with enzymes and turns into fat. When glucose is consumed almost none of it develops into fat. When fructose is consumed, 30% ends up as fat. (as shown in a study done on normal adults.) When the same adults were given a high fructose diet for just 6 days, their tryglicerides doubled, fat making went up 5 times and free fatty acids (which cause insulin resistance) doubled. As with alcohol, some of the fat produced when consuming fructose never makes it out of the liver. A fatty liver is an unhappy liver.
Fructose is not glucose. Fructose does not suppress the hunger hormone, ghrelin. If you drink a can of soda and then go out for fast food, you’ll eat more even though you’ve just consumed 150 calories. Fructose does not trigger insulin release. Insulin release triggers leptin release. Without leptin our brains don’t know that we’re full and we will continue to eat. The liver processes fructose completely differently than it does glucose. Massive fructose consumption alone will cause the development of Metabolic Syndrome: obesity, T2, lipid issues, cardiovascular disease and hypertension.
Fructose is not an acute toxin like alcohol is but, as shown above, it produces the same “bad stuff”. The brain doesn’t metabolize fructose therefore our bodies don’t give us a sign that we’ve had enough like it does with liquor. Wouldn’t it be nice if we got dizzy when we’d eaten too much fructose?
More stuff about fructose: there is an enzyme marker in the liver called ALT. Lots of ALT indicates a fatty liver. There have been studies that show the association between sugar-sweetened beverages (HFCS) and elevated liver enzyme marker, ALT. Ergo: consumption of sweetened beverages increases fat in the liver. When fructose is consumed, some free fatty acids come out of the liver and trigger insulin release. However, there is an enzyme created with fructose consumption that causes insulin resistance in the liver which makes the pancreas work that much harder. The higher your insulin level is, the harder it is for your brain to see leptin, which tells your brain that you are full. Fructose changes the way your brain recognizes energy, in a negative way. Vicious cycle: Fructose consumption increases insulin output, increased insulin suppresses leptin which means the brain doesn’t know that you’re full.
Chronic alcohol consumption creates a laundry list of 12 diseases/conditions. Fructose consumption has a list of 8 of the same diseases. Why? Because they do the same thing, they are metabolized the same way. Our government limits alcohol consumption but does nothing to limit our intake of fructose. In fact, it’s encouraged.
The American Heritage Medical Dictionary defines poison as: “A substance taken internally or applied externally that is injurious to health or dangerous to life.” Based on what I’ve learned in this video, I feel that in mass quantities (which we Americans are consuming), sugar, and especially fructose, is slowly poisoning us. It’s making us fat. It’s encouraging us to eat even more. It’s a slow killer and we invite it into our homes every single day. As I pointed out in my previous post, HFCS can be found in nearly every processed food we consume. The only way to avoid it is to cook your own fresh food and eat whole foods. My head is spinning from wading through all the science. I hope I’ve made it digestible for you.