When we digest carbs, the ultimate goal is to break them down to a usable form of energy, which is glucose. Our brain can only use glucose for fuel, thank goodness because the brain is primarily comprised of fat! The brain can also use ketones, which are byproducts of fat metabolism when we consume little to no carbs. Our kidneys are another organ that uses glucose as its primary fuel source. So the brain has to have glucose. No glucose means poor brain function which can range from poor memory to more serious conditions like Alzheimer's, Depression and Bi-polar disorder.
The brain uses about 4-6 grams of glucose per hour and the kidneys, significantly less, about 1 gram. If we do the math, this means our body only needs about 150 grams of carbs, or less, per day. Anything over that, and we are driving insulin up unnecessarily high, unless we are trying to gain weight. Remember, we have to have insulin but if we are not replenishing depleted glycogen stores, insulin drives glucose into the liver where it is converted to and stored as fat. If that isn't bad enough, when our insulin is high our brain is competing with it for glucose. And guess what?? If your brain isn't getting enough glucose, you know what it tells you to eat? That's right, more carbs...and before you know it, you are caught in a negative feedback loop that makes you crave carbs, diminishes cognitive function (stupid), store fat and develop insulin resistance (type-2 diabetes.)
Interestingly enough, our body has redundant systems to make sure our brain gets its glucose if we don't consume enough carbs. The body can do this by breaking down protein and fat. That's why there are essential fatty acids and amino acids...there are no essential carbohydrates. Simply put, we, as humans, are designed to function and be very healthy on a low carb intake, which makes sense since large amounts of carbs are relatively new to our diet. Nowadays, we are flooded with carbs everywhere we look and are told that we should have 6-11 servings per day!!! As usual, I am digressing...back to sugar.
There are several types of sugar. Here are four of the most common:
- sucrose (table sugar) a disaccharide made of one glucose and one fructose
- lactose (milk sugar) a disaccharide made of glucose and galactose
- galactose a monosaccharide found in animal products
- fructose (fruit sugar) found in...duh...fruit and is the sweetest of all the sugars
Here is the issue. Glucose is a primary metabolic fuel for the body...especially the brain. If the brain can't get enough glucose, the body uses fats and proteins as fuel or the brain tells the body to eat more carbs. Remember if insulin, a fat storage hormone, is high, our body loses the ability to metabolize protein and stored fat and our brain suffers. The message is simple; reduce the insulin load by reducing the carb load.
Over the history of our existence, our bodies have learned to metabolize glucose very efficiently in the liver. Now enter fructose. Even though fructose is classified as a sugar it is metabolized completely different than glucose. Once consumed, fructose is not allowed to enter the bloodstream and is absorbed and metabolized solely by the liver. What other substances are not allowed into the bloodstream and metabolized solely by the liver? Yep, toxins. Hmmmm...
When fructose, which is very sweet, enters the body we begin to produce a hormone called ghrelin which stimulates hunger. This makes sense, when we taste or smell something good; nature has programmed us to eat. Ghrelin levels are reduced when insulin goes up. What releases insulin? Elevated blood sugar. This also makes sense because if our blood sugar is going up that means we are getting carbs and have probably had enough to eat.
Here is the problem. When we consume fructose, our body can't use it, like other toxins, and the liver has to do something with it. So what it does is actually pull more glucose out of the blood into the liver and begins breaking down fructose. The end result is the liver turning fructose into fatty acids, some of which make it to the blood as triglycerides, and the others as fat deposits in the liver.
So short version: fructose pulls more glucose into the liver, which reduces the ghrelin/hunger response, which signals a person to keep eating, which raises insulin, which prevents the brain from getting what it wants, and increases fat storage and fat deposits on the liver...also called fatty liver disease...which is common in alcoholics…and we eventually become sick and obese. So fructose, in many ways, is metabolized like alcohol and other toxins and causes some serious health problems.
Some sources of fructose are:
- fruit, which when eaten in its natural state contain fiber which diminishes fructose absorption
- table sugar-sucrose (50% glucose and 50% fructose)
- High Fructose Corn Syrup (HFCS) (55% or more fructose, the rest glucose)...the worst of all. Sweeter than sugar, cheaper to make, and found in just about everything processed, sold in a box, sodas and....drum roll...kids juices and snacks.
Thanks to the soda companies, HFCS climbed from 3 million tons to 8 million tons in 1980. According to the
It is easy to now see how high levels of sugar and HFCS can cause a long list of health problems including behavioral and mood disorders. Check out these stats from the Center of Disease Control on ADHD and its rise in America. Hmmm...more disease=more medications=more $$ for drug companies. Also, don't know about you, but I see a correlation here...increase in carbs=increase in ADHD and related illnesses. If you ever google "ADHD diet" you will find a long list of recommendations that look almost identical to Paleo Diet....coincidence?
One of the theories about fructose consumption dates back to the evolution of humans. For the majority of our existence, carbs were very scarce and often available on a seasonal basis. Fruit is the primary source of fructose. Fruits are usually ripe and in season in the fall. The large amount in fructose in fruits drive hunger and allow us to gorge on carbs and to build an extra layer of fat which allows to survive the winter more easily. The point is we are designed to be very healthy with low carbs and occasionally gorge on carbs...unfortunely most folks get caught in the latter.
Ever heard that sugar is addicting? Well, it’s true. Sugar meets all the criteria as addictive drugs...except its legal, cheap and everywhere. Here are the criteria for addicting substances:
- Tolerance is developed
- Withdrawal
- Persistant desire
- Negative consequences
Here is a great article that Gary Taubes, author of Why We Get Fat recently wrote for the New York Times. In it, he writes about the history of HFCS in the American Diet and the associated rise in diseases and provides some compelling evidence.
If you have kids, this video is a must see. It is a lecture given by Dr. Robert Lustig. The video is a little over an hour long…I know, I know that’s pretty long, but he goes into the microbiology of fructose and shows how it is a toxin...and gives the simple version too.
This is the message guys. Limit or restrict the use of sugar and fructose. First start by identifying sources and cutting back on those sources and replace them with healthier choices, like healthy meats, fats or vegetables. Fruits are not bad. They contain fiber and nutrients, but since they contain fructose we should limit consumption to one to two servings per day. If possible, replace sugar or other sweeteners with natural organic honey. It may contain more calories per serving but it contains less fructose than table sugar. And get rid of all those fruit drinks!! They are loaded with fructose.
Studies have shown that occasional exposure to certain toxins like alcohol and fructose can be very healthy for the liver and ensures that it maintains its effectiveness at removing "bad" stuff. But, like all things, too much can be very harmful. Don't panic. This doesn't mean you can't have sugar again...because you can. It just means, by educating yourself with some useful knowledge, you can make better decisions for not only yourself but for you family as well. So, once again, if you don't take my word for it, please, seek out the knowledge and do your research...it can only help.
Every good write up. I had to share with my friends on facebook. Thanks for the info. Jami
ReplyDeleteThanks, glad you liked it and feel free to share it!
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