The Truth About Low Glycemic Foods

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Many dieters look for low glycemic foods to control hunger, avoid overeating and slim down. Some research studies suggest that a low glycemic diet can help you lose weight. But not all of the evidence is consistent and some popular beliefs about low glycemic foods may be wrong.

What Are Low Glycemic Foods

Many dieters believe that low glycemic foods are those that make your blood sugar rise at a slow and steady pace.

A low glycemic diet is based on the belief that you can curb overeating and maintain steady energy levels if you choose foods with a glycemic index value of 55 or lower.

Sample Low Glycemic Foods (GI Value of 55 or less)

  • Lentils
  • Grapefruit
  • Cashews
  • Yams
  • Hummus
  • Apple
  • Barley
  • Full fat or skim milk
  • Soy Beans

Low glycemic foods may also include high calorie or high fat foods like cake, corn chips or a Snickers bar.  Processed foods often carry a GI symbol to indicate that they have been tested to provide a low glycemic value.

Low glycemic foods are believed to be better for your diet than high glycemic foods like bread, white potatoes, white rice and sweetened sodas. High glycemic foods are believed to make your blood sugar spike quickly, followed by a dip that can cause hunger, decreased energy and a need to eat again.

Can Low Glycemic Foods Help Me Lose Weight?

The problem with eating low glycemic foods for weight loss is that these foods may not actually be better for your diet.

  I recently spoke to Susan Kleiner PhD, RD, FACN, CNS, FISSN to explain some of the myths about low glycemic foods. Dr. Kleiner is the owner of High Performance Nutrition in Mercer Washington, the author of several books on nutrition and has provided nutritional consultation for professional sports teams, elite and olympic athletes.

  She says that the premise on which low glycemic diets are based is wrong.

According to Kleiner, a glycemic index value does not indicate a food's speed of entry into the bloodstream.  "Glycemic index measures overall blood sugar over a period of time. You're not getting rate of absorption from that number," she says, referencing several clinical studies. "It might be a small difference in what we believe, but the small difference calls into question how we use the information."

What does that small difference mean for dieters? It means that low glycemic foods may not provide the slow, steady, diet-friendly blood sugar levels that they rely on. And high glycemic foods may not induce the blood sugar spike that can tempt overeating.

In addition, Kleiner says that low glycemic foods aren't always healthy or good for your diet.  She points out that ice cream is a low-glycemic food, but isn't necessarily a good choice if you're trying to lose weight. Even Crisco, she says, is a low-glycemic food.

And what about foods that carry the GI symbol? Kleiner says that dieters should be skeptical when they choose foods based on the label. "The GI symbol gives people a sense of security when there's really no justification for it."  She explains that some manufacturers are using the GI symbol as a marketing gimmick.  "They can add cheap fats to get a lower glycemic value and then get to use the GI symbol on the package." 

Low Glycemic Foods vs Healthy Foods for Weight Loss

So what's the best way to choose the best foods if you can't rely on the accuracy of the glycemic index? Kleiner says that dieters will benefit from eating whole foods that are full of nutrients. Those foods might be low glycemic foods, but not always, and the GI number can add confusion.

"I like for people to think about real food and not about abstract numbers," she says. Kleiner suggests making choices based on nutrient value and common sense. "The GI number can sometimes be used by dieters to justify eating less healthy foods like ice cream instead of fruit."  In the end, the healthiest food for your diet is the food that provides healthy nutrients with less processed fat and empty calories. Glycemic index may not always be the best guide to find those foods.

Sources:

Eelderink C1, Moerdijk-Poortvliet TC, Wang H, Schepers M, Preston T, Boer T, Vonk RJ, Schierbeek H, Priebe MG. "The glycemic response does not reflect the in vivo starch digestibility of fiber-rich wheat products in healthy men . " The Journal of Nutrition February 2012.

Coby Eelderink, Marianne Schepers, Tom Preston, Roel J Vonk, Lizette Oudhuis, and Marion G Priebe . "Slowly and rapidly digestible starchy foods can elicit a similar glycemic response because of differential tissue glucose uptake in healthy men ." American Journal of Clinical Nutrition September 18, 2012.

Schenk S, Davidson CJ, Zderic TW, Byerley LO, Coyle EF. . "Different glycemic indexes of breakfast cereals are not due to glucose entry into blood but to glucose removal by tissue ." American Journal of Clinical Nutrition October 2003.

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