FACTS: Good & Bad Sugars & Carbohydrates

I read in another post someone arguing that all sugars are the same chemically, and that therefore there is no such thing as good and bad sugar. I was pretty sure this was wrong so I did a bit of research.

Firstly - these are the different sugar types defined (Wikipedia):

Monosaccharides
Glucose, fructose and galactose are all simple sugars, monosaccharides, with the general formula C6H12O6. They have five hydroxyl groups (−OH) and a carbonyl group (C=O) and are cyclic when dissolved in water. They each exist as several isomers with dextro- and laevo-rotatory forms which cause polarized light to diverge to the right or the left.

Glucose, dextrose or grape sugar occurs naturally in fruits and plant juices and is the primary product of photosynthesis. Most ingested carbohydrates are converted into glucose during digestion and it is the form of sugar that is transported round the bodies of animals in the bloodstream. It can be manufactured from starch by the addition of enzymes or in the presence of acids. Glucose syrup is a liquid form of glucose that is widely used in the manufacture of foodstuffs. It can be manufactured from starch by enzymatic hydrolysis.

Fructose or fruit sugar occurs naturally in fruits, some root vegetables, cane sugar and honey and is the sweetest of the sugars. It is one of the components of sucrose or table sugar. It is used as a high fructose syrup which is manufactured from hydrolized corn starch which has been processed to yield corn syrup, with enzymes then added to convert part of the glucose into fructose.

Galactose does not generally occur in the free state but is a constituent with glucose of the disaccharide lactose or milk sugar. It is less sweet than glucose. It is a component of the antigens found on the surface of red blood cells that determine blood groups.

Disaccharides
Sucrose, maltose and lactose are all compound sugars, disaccharides, with the general formula C12H22O11. They are formed by the combination of two monosaccharide molecules with the exclusion of a molecule of water.

Sucrose is found in the stems of sugar cane and roots of sugar beet. It also occurs naturally alongside fructose and glucose in other plants, particularly fruits and some roots such as carrots. The different proportions of sugars found in these foods determines the range of sweetness experienced when eating them.[31] A molecule of sucrose is formed by the combination of a molecule of glucose with a molecule of fructose. After being eaten, sucrose is split into its constituent parts during digestion by a number of enzymes known as sucrases.

Maltose is formed during the germination of certain grains, most notably barley, where it is the source of the malt used in the manufacture of beer. A molecule of maltose is formed by the combination of two molecules of glucose. It is less sweet than glucose, fructose or sucrose.[31] It is formed in the body during the digestion of starch by the enzyme amylase and is itself broken down during digestion by the enzyme maltase.

Lactose is the naturally occurring sugar found in milk. A molecule of lactose is formed by the combination of a molecule of galactose with a molecule of glucose. It is broken down when consumed into its constituent parts by the enzyme lactase during digestion. Children have this enzyme but some adults no longer form it and they are unable to digest lactose.


Now the interesting bit:

All sugars are carbohydrates. Complex carbohydrates are considered "good" because of the longer series of sugars that make them up and take the body more time to break down. They generally have a lower glycemic load, which means that you will get lower amounts of sugars released at a more consistent rate — instead of peaks and valleys —to keep you going throughout the day.

Picking complex carbohydrates over simple carbohydrates is a matter of making some simple substitutions when it comes to your meals. "Have brown rice instead of white rice, have whole-wheat pasta instead of plain white pasta," says Meyerowitz.

To know if a packaged food is made of simple or complex carbohydrates, look at the label. "Read the box so you know what exactly you're getting. If the first ingredient is whole-wheat flour or whole-oat flower, it's likely going to be a complex carbohydrate,” says Meyerowitz. "And if there's fiber there, it's probably more complex in nature."


The glycemic index of a food basically tells you how quickly and how high your blood sugar will rise after eating the carbohydrate contained in that food, as compared to eating pure sugar. Lower glycemic index foods are healthier for your body, and you will tend to feel full longer after eating them. Most, but not all, complex carbs fall into the low glycemic index category.

It is easy to find lists of food classified by their glycemic index. You can see the difference between the glycemic index of some simple and complex carbohydrates in these examples:

White rice, 64
Brown rice, 55
White spaghetti, 44
Whole wheat spaghetti, 37
Corn flakes, 81
100 percent bran (whole grain) cereal, 38

To take this approach one step farther, you want to look at the glycemic load of a food. The glycemic load takes into account not only its glycemic index, but also the amount of carbohydrate in the food. A food can contain carbs that have a high glycemic index, but if there is only a tiny amount of that carb in the food, it won’t really have much of an impact. An example of a food with a high glycemic index but a low glycemic load is watermelon, which of course tastes sweet, but is mostly water.

for more details on gylcemic load, read here: http://www.everydayhealth.com/diet-nutrition/101/nutrition-basics/the-glycemic-load.aspx



Nowhere I looked stated that the type of sugar itself was good or bad for you: its all about how easy it is for your body to get at it, which is (I would hypothesise) why refined sugar is worse for you: its already been processed!


I am fully prepared to be corrected on any of the above: I hope you find this as useful as I did.