For years, many nutritionists, health practitioners, and even chemists told us all types of sugar are the same. And whether you eat an apple or a cookie, you metabolize it the same way.
Now we know they were wrong. Terribly wrong.
To help you understand why they were wrong, let’s talk a little bit about basic chemistry.
In basic chemistry, you define a molecule by its chemical composition. That is, by how many atoms it has. And by what kind of atoms it has.
Carbon, oxygen, and hydrogen atoms are the building blocks of life. And we call molecules made up of these three atomic components, “organic chemicals.”
We call carbon-based molecules with added hydrogen, “hydrocarbons.” And we use hydrocarbons to make energy (fuel) in non-living systems. For example, we burn coal to fuel power plants. (The downside to hydrocarbons is that they’re poisonous to living systems, like plants and animals.)
Similarly, we call carbon-based molecules with added oxygen and hydrogen, “carbohydrates.” And carbohydrates are important sources of energy to living systems. Put another way, humans need carbohydrates for energy.
We classify carbohydrates into two main groups: complex carbohydrates and simple sugars. Complex carbs include the starches, such as brown rice, wheat, quinoa, etc.
On the other hand, the simple sugars include:
– lactose (milk sugar)
– maltose (used in brewing beer)
– fructose (found in fruit)
– glucose (natural corn syrup)
These simple sugars have the same chemical composition. So, food scientists once considered them “identical.”
However, we can’t just consider the chemical composition of these sugar molecules. We now know that their “shape” is important too. For instance, chemical bonds can turn in one direction or the other. They can bend light in one direction or the other. And they can “fold” in one way or the other.
We call chemical molecules with the same composition but different shapes “chemical isomers.” And because of these subtle differences in shape, chemical isomers behave very differently in the body.
For example, the simple sugars fructose and glucose are chemical isomers. They have the same chemical composition. But they have different shapes. So, they behave very differently in the body.
Let’s look at fructose first.
Most fruits contain about 10 grams of fructose per serving. But as I’ve often pointed out, the body handles natural fructose quite well. Your body recognizes it. And metabolizes it quite easily.
Furthermore, no study has ever shown that fructose, in its natural form, negatively impacts health. In fact, newer studies link higher fruit consumption with lower body weight. And with fewer obesity-related diseases, like Type II diabetes.
This finding came as a rude awakening for some. As I said earlier, for years and years, dieticians, nutritionists and many doctors advised patients with Type II diabetes not to eat fruit because of its high sugar content.
But now we know this is poor advice.
As you’ll recall from a recent article, diabetics who upped their fruit consumption actually lost weight. And the added fruit in the diet didn’t affect their blood sugar levels one iota.
Of course, your body digests fruit relatively slowly. This slower digestion rate is the critical factor.
When you eat whole fruit, the fructose is taken in as part of the natural biomatrix. So you get the fructose, but you also get plenty of fiber. And the fiber slows the absorption of fructose from the intestines, primarily because it makes the contents thicker. This allows sugar to “trickle” into the bloodstream.
Lastly, fruits also contain high levels of micronutrients and antioxidants. And these help keep the liver in top metabolic shape. They also protect against inflammation. And prevent insulin resistance in the tissues.
Ultimately, all of these factors positively influence digestion and metabolism of fruit sugar.
Now, let’s move on to the chemical isomer glucose.
Remember, it has the same chemical make-up as fructose. Like fructose, it contains six carbon atoms. But its shape is different. And we know it behaves quite differently in the body.
And it tastes different too.
You may think glucose is sweeter than fructose. But it’s not. Amazingly, fructose is more than two times sweeter than glucose. In fact, pure glucose–found in natural corn syrup–is not very sweet at all. That’s why food manufacturers add fructose to sweeten it up, as I’ll explain in a moment.
Glucose also behaves very differently in the body. And your body metabolizes it differently. So, this has very marked health implications.
For example, glucose is a very potent stimulator of insulin secretion from the pancreas. In contrast, fructose does not directly stimulate insulin. Instead, the liver–your body’s primary metabolic organ–takes it up directly.
The real problems occur when you start eating a refined sugar like sucrose (table sugar).
Sucrose chemically combines equal amounts of fructose + glucose. And most processed foods on the market today contain sucrose, high-fructose corn syrup, or artificial sweeteners like aspartame.
In France, scientists found a striking difference between how your body processes these sugars. They discovered that consuming natural fruit juice (fructose) did not cause diabetes. Or even weight gain. But drinking beverages with table sugar (sucrose) did. And so did drinking artificially sweetened beverages, like diet soda.
Fructose simply isn’t the problem.
Men and women in the U.S. take in too many foods containing glucose, sucrose, and refined starches. These refined sugars contribute far more to the obesity epidemic facing this country.
Reduce your intake of all processed carbohydrates and starches. Avoid refined sugars like sucrose. And increase your intake of fruits. The watermelons taste like pure heaven this time of year.
1. “Examining the Health Effects of Fructose,” Journal of the American Medical Association, (www.jamanetwork.com), published online June 3, 20136/3/2012.