The glycemic diet has been become a popular way to lose weight. What is it? Well the glycemic index measures carbohydrates and that helps control your blood sugar levels. At first this diet was used to help diabetics but it is useful for weight loss as well. Here's the run down according to Kathleen Zelman, MPH, RD:
The glycemic index measures carbohydrates. The index is a list of how blood sugar levels rise after you eat a small portion of a carbohydrate food.
In general, all whole fruits and vegetables are healthy carbs, even if some are a little higher in natural sugars than others.
When trying to find the best quality carbs using the food label, Harvard researcher Dariush Mozaffarian, MD, recommends looking for carbs that are the least processed, whole grain, and contain plenty of fiber.
Another approach, Mozaffarian says, is to look at the ratio of total carbohydrates to dietary fiber per serving. This figure includes sugars, and when the ratio is 10:1 or more, keep looking until you find one that is less than 5:1.
If that is too complicated, try following the guidance from My Plate, the U.S. Department of Agriculture's dietary guidelines, which will help you make healthier choices. That includes filling half your plate with vegetables and fruits, and the other half with grains and proteins.
"It is better to focus on eating an overall healthier diet (fruits, vegetables, beans, whole grains, healthy fats, lean protein, low-fat dairy, nuts), increase fiber intake, and decrease processed foods," Warshaw says.
All carbohydrates increase blood sugar levels, but the effect varies widely. For example, a glass of orange juice will cause a much quicker rise in blood sugar than a bowl of oatmeal, which takes longer because of the type of carbohydrate and amount of fiber.
The response is affected by many factors, including the quantity of food, the amount and type of carbohydrate, the cooking method, degree of processing, and more.
On the glycemic index scale, each food is assigned an index number from 1-100, with 100 as the reference score for pure glucose. Typically, foods are rated high (greater than 70), moderate (56-69), or low (less than 55).
Quality Carbs Promote Weight Loss
Using the glycemic index (GI) in diet plans is based on the concept that low-glycemic foods are more satisfying than high-glycemic foods. Low-GI foods take longer to absorb and help dieters feel full longer, so they are less likely to overeat. High-GI foods break down faster, leaving you hungry and less satisfied.
Most, but not all, foods on the lower end of the GI scale tend to be healthier, nutrient-rich, less processed, and higher in fiber -- such as whole fruits, vegetables, grains, and beans. Foods high in fiber can be very filling, especially when paired with protein.
"When you focus on choosing low-GI carbs along with lean protein and healthy fats, you will naturally crowd out many of the less nutritious, high GI foods and lose weight,” says David Ludwig, MD, PhD, founder of the Optimal Weight for Life program (OWL) at Children's Hospital Boston. He has used the GI plan successfully for years with his patients.
Whereas the higher GI foods "trigger a rise in blood sugar, followed by a cascade of hormonal changes, which tend to make you hungry again sooner because they are metabolized quicker than low-GI foods," says Ludwig, author of Ending the Food Fight, a weight loss book using the glycemic index.
Glycemic Index Controversy
The GI is not a perfect tool and is no guarantee of healthy fare. Brown and white rice rank comparably on the index scale as do white and whole wheat bread, yet clearly the whole grain choices are healthier.
Some scores are confusing. For example, carrots are a nutrient-rich, high-fiber vegetable that can range from low to high on the GI scale. Likewise, some candy that includes nuts gets a better GI score than a potato. Ripe bananas have higher GI scores than under-ripe bananas. Cook pasta al dente and it ranks lower than fully cooked pasta.
Not only do the food scores vary, but so does the response from person to person. It can even vary within the same person from day to day, according to research reported in the June 2007 issue of Diabetes Care.
Furthermore, no one eats a single food in isolation. When carbs are paired with other foods, it impacts how blood sugars are affected -- that's the glycemic load, which ranks foods based on carbs and portion size.
Some nutrition experts don’t put much stock in the GI as an effective weight loss tool because of all the variability associated with the numbers.
"Using the GI to lose weight is unnecessarily complicated, and it does not simplify the task of choosing healthier food to lose weight or manage blood sugar," says Hope Warshaw, MMSc, RD, a certified diabetes educator and author of books about diabetes including Diabetes Meal Planning Made Easy.
Some experts see the glycemic index as just another gimmick because there is little evidence that an elevated blood sugar level leads to weight gain if you are healthy.
How to Choose Healthier Carbs
"Look at the bigger picture. Use the GI scale to choose quality
carbs that are healthy, natural, whole, and in the least processed
state," Ludwig says.
There is no such thing as one-size-fits-all for weight control. And no single factor defines the perfect nutritional diet.
If you don't get too hung up on the numbers and use common sense to select healthy, less processed, wholesome carbs, a glycemic index diet can help you choose healthier carbs. Keep in mind that you must also control portion sizes and total calories, and get regular physical activity.
Any diet you can stick with long term is the right one for you. "Make healthy food choices that you can live with forever because there really is no value in going on a diet plan for two weeks if you can’t sustain it," Warshaw says.
Further research is needed to reach consensus on whether the glycemic index works as a long-term weight loss plan.
Kathleen Zelman, MPH, RD, is director of nutrition for WebMD. Her opinions and conclusions are her own.