FORMS OF CARBOHYDRATE

 forms of carbohydrate:

• monosaccharides,



• oligosaccharides, and



• polysaccharides.



Let’s look at each separately.


MONOSACCHARIDES

Monosaccharides are often called simple carbohydrates because they have a simple structure. Mono means one and saccharide means sugar. So, one sugar.

The monosaccharides are…

• glucose,



• fructose, and



• galactose.



Glucose is a type of sugar also known as blood sugar, which is found in our blood and produced from the food we eat (most dietary carbohydrates contain glucose, either as the sole form of sugar or combined with the other two simple sugars given above). When people talk about “blood sugar levels,” they’re talking about the amount of glucose floating around in the blood.

Fructose is a type of sugar naturally found in fruit and also found in processed products like sucrose (table sugar) and high fructose corn syrup (HFCS), both of which are about 50 percent fructose and 50 percent glucose. Fructose is converted into glucose by the liver and then released into the blood for use.

Galactose is a type of sugar found in dairy products, and it’s metabolized similarly to fructose.


OLIGOSACCHARIDES

Oligosaccharides are molecules that contain several monosaccharides linked together in chain-like structures. Oligos is Greek for “a few,” so oligosaccharides means “a few sugars.”

Oligosaccharides are one of the components of fiber found in plants. Our bodies are able to partially break down oligosaccharides into glucose (leaving the fibrous, indigestible parts behind to do good things in our guts).

Many vegetables also contain fructo-oligosaccharides, which are short chains of fructose molecules. The body metabolizes these accordingly (it breaks the chains, and then it converts the individual fructose molecules into glucose for use).

Another common form of oligosaccharide that we eat is raffinose, which consists of a chain of galactose, glucose, and fructose (called a trisaccharide), that can be found in whole grains and in vegetables including beans, cabbage, Brussels sprouts, broccoli, and asparagus, other vegetables, and whole grains.

Galactooligosaccharides round out the list of oligosaccharides and are short chains of galactose molecules. These are indigestible but play a role in stimulating healthy bacteria growth in the gut.


POLYSACCHARIDES

Polysaccharides are long chains of monosaccharides, usually containing 10 or more monosaccharide units. Poly is Greek for “many” and accordingly, these molecules consist of many sugars.

Starch (the energy stores of plants) and cellulose (a natural fiber found in many plants) are two examples of polysaccharides that we often eat. Our bodies are able to easily break starches down into glucose, but not cellulose: it passes through our digestive system intact (making it a source of dietary fiber).


THERE’S A PATTERN HERE…THEY ALL END UP AS GLUCOSE

As you’ve probably noticed, all forms of carbohydrate we eat are either metabolized into glucose or are left indigested, serving as dietary fiber.

Our body can’t distinguish between the natural sugar found in fruit, honey, or milk and the processed sugar found in a Snickers bar. They’re all digested in the same way: they’re broken down into monosaccharides, which are then turned into glucose, which is then shipped off to the brain, muscles, and organs for use.

Yes, in the end, the candy bar turns into glucose just like the cup of peas. Sure, the candy bar turns into glucose faster, but that’s the only difference (carbohydrate-wise). The candy bar has a bunch of monosaccharides that are quickly metabolized, whereas the peas have a bunch of oligosaccharides that take longer to break down.

Now, I’m not saying peas are “the same as” candy bars, so dump the veggies and bring on the chocolate. Obviously, peas are more nutritious than Snickers bars, but there’s more to this story.

Chemically speaking, simple carbohydrates like the sugar and HFCS found in processed foods are pretty simple. Table sugar, or sucrose, is a disaccharide (two sugars) consisting of one part fructose and one part glucose. Sucrose occurs in natural foods like pineapples, sweet potatoes, beets, sugarcane, and even walnuts, pecans, and cashews. It’s also added to foods to make them sweeter.

HFCS is chemically similar, usually consisting of about 55 percent fructose and 45 percent glucose. It isn’t found in nature (it’s artificially produced) and the only difference between it and sucrose is the fructose and glucose aren’t chemically bonded, which means the body has to do even less work to metabolize it into glucose.

Now, when viewed that way, neither seems all that nefarious. The sucrose found in a pineapple is no different chemically than the sucrose in our favorite type of dessert. And HFCS is chemically similar to sucrose.

What’s the big deal, then? Why are we told that eating the sucrose in a pineapple is okay but the chemically identical sucrose in the chocolate bar or some other form of simple carbohydrate is disastrous? Why is HFCS often vilified as the ultimate metabolic miscreant when it’s pretty dang similar to sucrose?

Well, while it’s true that some people’s bodies do better with carbohydrates (all forms) than others, it’s simply not true that sucrose, HFCS, or other simple forms of carbohydrate are especially fattening.

As you now know, these two molecules just aren’t that special. They are just a source of glucose for the body like any other carbohydrate.

Don’t believe me? Well, let’s look at some research.

In one study, researchers from the Sugar Bureau in the UK (tasked with researching all forms of sugars, not with convincing us to eat a bunch of sucrose or HFCS) set out to determine whether there should be a guideline for daily sugar consumption.

They found that increased sugar intake was associated with leanness, not obesity, and concluded that there simply wasn’t enough evidence to warrant a quantitative guideline for sugar consumption.

Another study, conducted by researchers at the University of Hawaii, extensively reviewed sugar-related literature.
Here’s a quote from the paper:


“It is important to state at the outset that there is no direct connection between added sugars intake and obesity unless excessive consumption of sugar-containing beverages and foods leads to energy imbalance and the resultant weight gain.”


Overconsumption and energy imbalance are the keys here.

You see, it’s a known fact that over the past couple of decades, Americans have increased the number of calories they eat every day, and much of this increase is in the form of carbohydrates, primarily from soft drinks.

This is where we get to the actual problem with sugar and HFCS intake and getting and staying fat: the more you eat foods with added sugars, the easier it is to overeat.

This is especially true of liquid carbohydrates, including beverages with added sugar.

If you love caloric beverages, you’ll probably stay fat forever. You can drink 1,000 calories and be hungry an hour later, whereas eating 1,000 calories of high-quality food, including a good portion of protein and fiber, will probably keep you full for five to six hours.

And what about HFCS? What does the literature reveal about this sucrose-like molecule? More of the same, of course.

Here’s a quote from an extensive review of HFCS literature published in 2008:


“Sucrose, HFCS, invert sugar, honey, and many fruits and juices deliver the same sugars in the same ratios to the same tissues within the same time frame to the same metabolic pathways. Thus…it makes essentially no metabolic difference which one is used.”


Here’s one from an HFCS literature review conducted by researchers from the University of Maryland and published in 2007:


“Based on the currently available evidence, the expert panel concluded that HFCS does not appear to contribute to overweight and obesity any differently than do other energy sources.”


And yet another from yet another literature review published in 2008:


“The data presented indicated that HFCS is very similar to sucrose, being about 55 percent fructose and 45 percent glucose, and thus, not surprisingly, few metabolic differences were found comparing HFCS and sucrose. That said, HFCS does contribute to added sugars and calories, and those concerned with managing their weight should be concerned about calories from beverages and other foods, regardless of HFCS content.”


The bottom line is that HFCS is just another simple sugar, and as far as we can currently tell, it can only harm us when overconsumed.

Now, at this point, you’re probably thinking that you have carte blanche to eat as much sugar and as many simple carbohydrates as you want. While doing so may not be as harmful as you’re told, there’s more to consider.