HEALTH MATTERS
8.1.15
CONTACT: LYNN SCRIBNER
903-731-5329
Will Slow Carbs Help You Lose Weight?
When you see or hear the word “glycemia,” you probably think first of diabetes. And with good
reason: it means the state of having sugar in the blood.
The glycemic index (GI) and diets based on it were originally developed to help diabetic patients
make food choices to help them control their blood sugar. More recently, the index has become a
guiding factor in many popular commercial diet plans such as the South Beach, Sugar Busters, Slow-Carb
and Zone diets.
The idea in most of these eating plans is not to simply limit carbohydrates (as in the Atkins diet)
but to focus on carbohydrates that are least likely to cause a large, rapid increase in blood sugar levels.
In other words, it’s not low carb but slow carb.
Carbohydrates come in three basic forms: sugars, starches and fiber. The sugar and starches are
both broken down in your body into glucose. If you have diabetes, that is the source of your problem. If
you don’t have diabetes, sugar in your blood prompts your pancreas to release insulin, which allows
glucose to move out of your blood and into cells to be used as energy. Too much sugar means a surge of
insulin and two consequences you probably don’t want. Your body stops burning fat and starts storing it
instead. And when sugar has been removed too quickly from the blood, you get hungry and are
prompted to eat more.
Avoiding these blood sugar/insulin rebounds is a reason many dieters choose the low carb
approach. But in doing so, they are also likely to ignore complex carbohydrates such as fruits, vegetables
and whole grains–most of which provide nutrients and fiber that are essential to good health.
Complex carbohydrates are generally low GI, but the distinction between low carb and slow carb
goes beyond complex and simple carbs.
Simply put, a food’s glycemic index represents how rapidly a carbohydrate food raises blood
glucose compared to table sugar or white bread. The latter have a GI of 100; raw carrots, 5, according to
the Glycemic Index database in Sydney, Australia.
Low GI foods are those with a score of 55 or lower. These include: celery, 0; kidney beans, 23;
fresh cherries, 22; and oatmeal, 49. Medium GI foods (55-70) include rye bread, 58; new potatoes, 62;
and tortilla chips, 63. Rated at high GI (higher than 70) are cake doughnuts, 76; french fries, 75; and
fresh watermelon, 72.
The 72 score for watermelon is telling. You have to eat a lot of watermelon to get up to the test
level of 50 grams of digestible carbohydrates. This problem is addressed through what is known as
glycemic load (GL), defined as the change in glucose level following consumption of a typical serving. The
GL for four ounces of watermelon, a more typical serving, is only 5.
Both glycemic index and glycemic load can be found at the Sydney University website. They are
useful tools whether you are trying to control your blood sugar, your weight or your appetite. But these
scores don’t necessarily tell you anything about the health benefits of a food. A four-ounce slice of
chocolate cake, for example, has a GI of 38 (low) while a half cup of bran flakes cereal has 74 (high).
Glycemic index also varies with the way food is cooked. Al dente pasta has a lower number than
soft-cooked pasta. Generally, the more a food is cooked or processed, the higher its GI.
A ripe banana is higher than a green one. Raw fruit is lower than juice.
As you might expect, old fashioned oatmeal ranks lower than the instant version. And there are
some variations that are hard to figure out. Long grain white rice is lower than brown rice, but brown
rice is lower than short grain white rice.
If you’re using the glycemic index to manage your diabetes, you need other help as well–
nutritional advice, carbohydrate counting, meal planning and common sense.
As for losing weight or gaining health benefits, the low GI diets have much to recommend them.
The research regarding their effectiveness, however, is mixed.
A 2013 review of 23 published studies concluded that low glycemic index diets were “as
effective as other dietary alternatives in inducing weight loss.” A key argument for the low GI diets
involves appetite control, a slower return of hunger after a meal or snack. Studies, however, have
generally not found that persons following a low-GI diet ate less or managed their weight better over
the long term compared to those following other weight loss plans.
Whether you choose a slow carb approach or not, understanding the glycemic index may help
you increase your intake of fruits, vegetables, fiber, potassium and other important nutrients.