Carbohydrates: How to distinguish the good carbs from the bad

Heres some bizarre logic: Encourage women of childbearing age (well call these millions of women WOCBA) to eat highly processed bread products because thats the only way many of them will get enough folic acid to avoid the risk of birth defects.

That advice comes from Anita Boles, executive director of the US National Healthy Mothers, Healthy Babies Coalition. Specifically, Ms. Boles is concerned that too many WOCBA may be caught up in the hype about low-carbohydrate diets. If they remove processed bread from their diets (the reasoning goes), they wont be getting a sufficient amount of folic acid that refined grain products are fortified with.

Hmmm. Couldnt WOCBA just go to a health food store and purchase folic acid supplements?

Nope, not good enough, says Ms. Boles. Statistics show that 60 percent of the women in this group fail to take the recommended daily dose of 400 mcg of folic acid.

So lets see if Ive got this straight. Since well over 50 percent of WOCBA dont take the simple step necessary to help prevent birth defects, the best solution is that they should be encouraged to eat plenty of unhealthy fortified carbs? Of course, those arent Ms. Boles words. She describes them as enriched grains.

Well, call them what you want. A daily intake of highly processed grain products simply adds up to enriched poor nutrition.

Happily, though, on the same day I came across the item with Ms. Boles advice, I happened to find an article from a mainstream media outlet that actually offers some surprisingly clear thinking about carbohydrates.

Measuring up
Heres some sound logic in a Reuters Health headline: Carbohydrate Type, Not Amount, Linked to Obesity.

After all the media hype over the past few years about the pros and cons of carbohydrate intake, its about time that someone in the mainstream started making the obvious and very important distinction between good carbs and bad carbs.

The Reuters report details an observational study conducted by US researchers at the University of Massachusetts (UM) Medical School and published in the American Journal of Epidemiology. Over a period of one year, the UM team collected dietary and physical activity information from more then 570 healthy adults. Height and weight measurements were also monitored.

Researchers calculated each subjects body mass index (BMI: a measurement that factors in both height and weight) and noted BMI changes over the course of the year. Foods consumed by the subjects were measured against the glycaemia index (GI), a measurement system that assigns a low GI to foods (such as most fruits and vegetables) that prompt a slow increase in blood sugar levels, and a high GI to foods (such as processed baked goods and starchy foods) that produce a quick spike in blood sugar levels. A daily intake of high GI foods promotes obesity and a gradual insensitivity to insulin; the precursor of Type 2 diabetes.

Using these measurements, the UM team found that the higher the BMI a subject had, the more likely they were to eat a high GI diet. The lead researcher, Dr Yunsheng Ma, told Reuters Health that overall carbohydrate intake had no effect on BMI. In Dr. Mas words: Its the type of carbohydrate thats important.

 
Carbs 101
I asked HSI Panellist Dr Allan Spreen to explain the difference between good carbs and bad. He started by noting that carbohydrate foods are basically broken down into two groups: simple and complex carbohydrates. And both of these groups are further broken down into refined and unrefined.

Beginning with refined simple carbohydrates (which includes all sugars), Dr. Spreen notes that refining creates three problems:

1) Removal of nutrients required for the metabolism of the contained sugar
2) Concentration of the sugar within the simple carb food, overstressing the pancreas
3) Removal of fibre needed to slow the release of sugar into the system

Its the fibre in fruits - which are unrefined simple carbohydrates - that helps make the sugar in fruit so much healthier than the sugar in refined carbs.

Complex carbs are the edible starches: flour, bread, cereals, grains and most vegetables. And while complex carbs are, generally speaking, better than simple carbs, refining plays a key role here too. Dr. Spreen explains: The same principles apply in the case of refined complex carbs as to the simple ones: the sugars can be concentrated; they can have the necessary nutrients as well as the fibre removed.

As soon as a starch hits enzymes in your mouth, the starches begin the digestion process, and breaks down to (you guessed it) sugar. If those starches start without the nutrients and especially the fibre they originally contained, they are not only inferior foods, but theyre also inferior foods with automatically concentrated starches, because the fibres gone. As soon as the starch breaks down to sugar, youre back to a refined simple carb.

Fortunately, the glycaemia index can help guide your food choices away from the types of carbohydrates that promote obesity and insulin insensitivity. The University of Sydney maintains a web site (glycemicindex.com) where you can search the GI of different types of food. The slight drawback is that the database is sometimes specific about brand names, some are European although most are Australian. Nevertheless, the database still offers an excellent guide for making low GI dietary choices.