4 reasons why the glycemic index is outdated | livestrong.com (2023)

4 reasons why the glycemic index is outdated | livestrong.com (1)

If you are living with diabetes, counting carbohydrates is a smarter strategy than focusing on the glycemic index of foods.

Author of the photo:BakiBG/E+/GettyImages

The glycemic index has long been used as a tool to assess a food's effect on blood sugar levels, but it is not without its flaws.


We asked registered dietitians and an endocrinologist to explain how useful the glycemic index (GI) is for people trying to control their blood sugar and what to focus on.

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What is the glycemic index?

"The glycemic index is a metric that measures how certain foods raise blood sugar levels," he explains.Christine Russell, RD, CDCES, Registered Dietitian and Diabetes Care Instructor and Education Specialist with Nutrition Counseling Companynurture.


Developed by doctors in 1981, the GI attempts to quantify the effects of food on blood sugar levels compared to sugar. Glucose (also known as sugar) has a GI of 100. Other foods are numbered from 0 to 100, with the number indicating how much a food tends to raise blood sugar levels compared to glucose. This is how it looks in practice:

  • Low GI foods‌: those that tend to cause a slow and steady release of glucose into the bloodstream; they are assigned scores from 1 to 55mayo clinic.
  • Medium GI foods‌: These fall in the range of 56 to 69.
  • High GI foods‌: This often results in rapid spikes and then drops in blood glucose levels and a score of 70 or higher.


(Video) Limitations of the Glycemic Index

The IG has been touted as a useful tool for those looking for it.Optimize your diet for diabetesManagement.

The reasoning is that "foods with a high glycemic index would be less ideal for people with diabetes because they are more likely to cause spikes and crashes in blood sugar, which is not only unfortunate from the point of view that it can do make the person feel uncomfortable, but they do." It's also hard to figure out the right dosage for insulin medications and treatments," she says.Maryann Walsh, RD, CDE, registered nutritionist, certified diabetes educator, and founder of the Walsh Nutrition Clinic.


On the other hand, "low-glycemic foods would be better because they cause fewer spikes and dips in blood sugar," says Walsh.


Why the Glycemic Index Isn't Always Helpful

Understanding how certain foods affect blood sugar levels is certainly helpful, whether or not you've been diagnosed with diabetes. But GI misses out on some key factors in this equation.


Here are four reasons why the GI isn't the most useful tool when it comes to choosing blood sugar-friendly foods.

1. Portion sizes are not taken into account

First things first: "The glycemic index doesn't take into account how much we actually consume at one time," Russell says.


(Video) High Glycemic Foods To Avoid – Dr. Berg

That is, glycemic index values ​​were assigned to foods based on a serving of that food containing 50 grams of carbohydrate. This serving size makes sense for some foods. For example, you would need to eat about 1 cup of cooked white rice (which has a GI of about 73) to get 50 grams of carbs from that meal. This is an absolutely realistic portion of rice.

However, you would need to eat about 7 whole cups of watermelon (which has a GI of about 76) to get 50 grams of carbs from the fruit. Most people don't eat that much watermelon at one time, so the fruit's high GI may not be that significant.


"Serving sizes give a more accurate picture of how a given food affects blood sugar during a meal," Russell says. This is why the “glycemic load” was created. Unlike the GI, the glycemic load is responsible for both the glycemic index ‌mi‌ the portion actually consumed.

Take this watermelon for example. fallsalternative‌ on the glycemic index, but ‌low‌ in terms of glycemic load (which is only 8) once a standard serving size is considered, e.g.Oregon State University.


2. The glycemic index of foods can change

Several variables can alter the glycemic index of a food.

"Certain preparation methods or even natural processes like fruit ripening can change the GI of a food," Walsh explains. “For example, the riper the plantain, the higher its GI. In terms of preparation methods, rice is an example of a food that has a higher GI when freshly prepared, but a lower GI after cooling and then reheating. "

This change has to do with the formation ofresistant starchon carbs cooked and then chilled.

3. Focus on a single macro

One of the shortcomings of the GI is that it focuses on a single macronutrient, carbohydrates, rather than the entire nutritional profile of a meal.

For example, we often eat carbohydrates like rice or potatoes along with other foods, not entirely on their own. Combining starches with other foods, such as chicken for lean protein and broccoli for fiber, slows down how quickly those starches are digested, in turn raising blood sugar levels.

"Eating carbohydrates alone is more likely to raise blood sugar faster and more dramatically than eating carbohydrates with a lean protein orhealthy source of fat', dice Walsh.

While GI advocates encourage people to calculate the glycemic index of foods based on the specific value of each component, the process can be tedious and potentially flawed. In fact, estimates of the glycemic index of whole foods overestimated their values ​​by up to 50% compared to first-hand measurements of the actual GI of meals in a small October 2011 study.american journal of clinical nutrition.


(Video) Glycemic Index - Does It Really Matter?

4. Some high GI foods are very nutritious and some low GI foods are not.

Focusing solely on the GI of a food means that other essential nutrients for diabetes may be overlooked.

"High glycemic index [carbohydrates]like whole wheat bread and oatmeal contain fiber," Russell says. "Fiber acts as a physical barrier and slows the release of sugar into the bloodstream."

The problem also turns to the other side. "Not all low GI foods are ideal choices and can actually be low in nutrients and high in saturated fat," Russell explains. “For example, French fries have a lower GI than oatmeal and sweet potatoes; However, oats and sweet potatoes contain more nutrients, less fat, and more fiber."

"The utility of the GI is clearly very subjective and nuanced, like most other aspects of nutritional science," says Walsh. "Two foods can [both] have a high GI, but they can differ in terms of overall nutritional benefit to the person when we consider [other nutrients such as] vitamins and minerals."


The way we metabolize carbohydrates is also very individual. "Genetics may play a role in regulating blood sugar due to mutations in certain receptors or proteins that are important for glucose metabolism," he says.Dra. Deena Adimoolam, specialist in endocrinology, diabetes and metabolism.

"In addition, [level of] insulin sensitivity and resistance play a huge role in how food affects blood sugar."

What to focus on instead

oDietary Guidelines for Americans 2020-2025He mentions the glycemic index... not at all. Take this as a sign that the tool is not a mainstay of blood sugar control.

These tips may be more helpful in optimizing your stats.

1. Reduce your total intake of added sugars

If you want to make your diet more compatible with your blood sugar, start by remembering your daily added sugar goal.


oAmerican Heart Associationrecommends limiting added sugars to no more than 6% of calories per day, which works out to 24-35 grams per day, depending on how many calories you eat.

"This is also a good rule of thumb for people with diabetes," says Walsh.

Check Nutrition Facts labels for the amount of added sugar in commonly sweetened foods, such as soft drinks, yogurt, breakfast cereals, and packaged snacks. Keep in mind that the amount of added sugar listed on the label is for a single serving of the food. So you need to multiply that amount of added sugar if you want to eat more than one serving.


"The American Diabetes Association doesn't give specific sugar recommendations, but instead focuses on total grams of carbohydrates to control blood sugar," Russell says.

(Video) Glycemic Index Explained For Diabetics {New Warnings}

2. Combine carbs with protein and healthy fats

“My general advice for those looking to improve their blood sugar is… combine simple carbohydrates like bread or pasta with something that contains protein, like meat or cheese.delay a rise in blood sugarsaid Dr. Adimoolam.

Rapid spikes and dips in blood sugar levels can trigger hunger, which can lead to increases in caloric intake that may not align with weight management or carbohydrate intake goals, he adds.

Here are some pairing examples.carbohydrate foodswith lean protein and healthy fats to mitigate post-meal blood sugar spikes:

  • Instead of a plain bagel, opt for a whole wheat bagel (carbs) + salmon (healthy fats and protein) + avocado (healthy fats)
  • Instead of plain pasta with tomato sauce, go for whole wheat pasta (carbs) + chicken sausage (lean protein) + vegetables + pesto (healthy fat)
  • Instead of chips, go for crackers (carbs) + almonds (healthy fats and protein) + shredded cheese (healthy fats and protein)

3. Increase your fiber

Glycemic index values ​​do not always match the fiber content of a food, andeat enough fiberit is an essential part of blood sugar control. This is because non-digestible carbohydrates help slow the rate at which sugar enters the bloodstream, preventing spikes in glucose levels.

Whether diagnosed with diabetes or not, all adults should aim for 14 grams of fiber for every 1,000 calories consumed daily (with fiber from whole food sources like vegetables, fruits, whole grains, and beans) according to the Dietary Guidelines. 2020-2025. for the americans

4. Work with a professional

A moderate carbohydrate diet (‌NO‌ a bass orno carb diet) is the leading nutritional intervention for blood sugar control, Russell says.

Although the glycemic index can be a useful tool when used in combination withcarb countKnowing how to eat the right amount and type of carbohydrates for your body and your blood sugar is helpful.

Get support from board-level health professionals like board-level endocrinologists and registered dietitians who can teach you carb counting and optimal eating habits for blood sugar control. Chances are, your personalized plan will go beyond the glycemic index.




What are the limitations of the glycemic index? ›

One of the major drawbacks of glycemic index is that the glycemic response to a particular food varies between individuals as well from day to day and even throughout different points in the day. The glycemic index of different types of foods can vary according to several factors.

Why is the glycemic index bad? ›

Studies have associated diets with a high GI (higher process foods) and high glycemic load (larger portions) with an increased risk of developing diabetes, heart disease and some cancers. Data suggests that eating low-GI foods (whole foods, less processed foods) controls blood sugar and insulin levels.

What factors affect glycemic index? ›

The glycemic index is a tool that's often used to promote better blood sugar management. Several factors influence the glycemic index of a food, including its nutrient composition, cooking method, ripeness, and the amount of processing it has undergone.

Is glycemic index still used? ›

A low-GI diet uses the glycemic index as the main guide for meal planning. People also may use the glycemic index as one of many tools for making choices about foods and meals.

Is the glycemic index reliable? ›

Individual response to glycemic index values vary so much that it may not be useful in indicating blood sugar response, says research published in the American Journal of Clinical Nutrition.

What are the disadvantages of low glycemic index? ›

The main disadvantage of low GI diets for people with diabetes comes if the overall carbohydrate content of meals is too high for the body to comfortably cope with. For example, a large portion of a bran based cereal for breakfast will typically be low GI but could contain a relatively high value of carbohydrate.

What is glycemic index and why does it matter? ›

The glycaemic index (GI) is a rating system for foods containing carbohydrates. It shows how quickly each food affects your blood sugar (glucose) level when that food is eaten on its own.

Is glycemic index bad for diabetes? ›

In general, low GI foods increase glucose slowly in your body. Foods with a high GI increase blood glucose quickly. If you have diabetes, high GI foods can make it harder to control diabetes.

What makes foods lower glycemic index? ›

Williams notes that foods higher in fat and protein “tend to be absorbed slower, and therefore have a lower glycemic index. But the glycemic index isn't necessarily a measure that's easy to use as a nutrition guide, the way that you can with calories.

What is the critique of glycemic index? ›

Recent criticisms of the glycaemic index (GI) focus on its validity with assertions that GI methodology is not valid, GI values are inaccurate and imprecise, GI does not predict what foods are healthy and that whole grain and fibre are better markers of carbohydrate quality than GI.

What is a limitation to the use of glycemic index quizlet? ›

A major limitation of the glycemic index is that a food's glycemic index is affected by many factors: how the food is prepared, who eats it, what other foods might be eaten previously or at the same time, the time of day, etc. This wide variability limits the usefulness of the glycemic index.

Can glycemic index change? ›

It could be different on your plate, depending on several things. Preparation. Fat, fiber, and acid (such as lemon juice or vinegar) lower the glycemic index. The longer you cook starches like pasta, the higher their glycemic index will be.

Is glycaemic index GI an unreliable predictor of how foods affect blood sugar levels? ›

High variability suggests glycemic index is unreliable indicator of blood sugar response. Summary: The glycemic index value of a food can vary by 20 percent within an individual and 25 percent among individuals, according to the results of a controlled feeding trial in 63 healthy adults.

Which is more accurate glycemic index or load? ›

By including the amount of carbs you are given a better sense of how your body is processing the serving. Glycemic load is more accurate than the glycemic index in predicting how your body will process sugar.

Is glycemic index more important than sugar? ›

Glycemic load diet

The bottom line? Following the principles of low-glycemic-index eating is likely to be beneficial for people with diabetes. But reaching and staying at a healthy weight is more important for your blood sugar and your overall health.

What are the advantages and disadvantages of low GI diet? ›

Studies have shown that the low GI diet may result in weight loss, reduce blood sugar levels, and lower the risk of heart disease and type 2 diabetes. However, the way it ranks foods has been criticized for being unreliable and failing to reflect foods' overall healthiness.

What is one of the shortcomings of the glycemic index chegg? ›

The glycemic index has a significant disadvantage because it does not account for insulin synthesis due to blood sugar fluctuations. As a result, there can be two foods with the same glycemic index but distinct insulin production.

Why is it better to eat foods with a low glycemic index rather than a high glycemic index? ›

a low glycemic index diet can help maintain weight loss. a high glycemic index increases the risk of breast, prostate, colorectal, and pancreatic cancers. a high glycemic index diet increases the risk of developing type 2 diabetes and cardiovascular disease.

Does glycemic index affect A1C? ›

Low glycemic index diets improved A1C by a weighted mean difference of 0.5 percent when compared with high glycemic index diets (95% confidence interval [CI], −1.0 to −0.1; P = . 03) and a measured carbohydrate exchange diet (95% CI, −0.9 to −0.1; P = . 02).

What happens when you eat foods with high glycemic index? ›

Eating high-GI foods can cause blood sugar levels to rapidly rise — triggering the pancreas to release more insulin — and then quickly fall. This can promote cravings and overeating.

Why don t meats and fats have a GI score? ›

Things like meat, oils and fats have a GI of zero, since they contain no carbs. Carbohydrate-containing foods fall into different GI categories based on scientific measurements of glucose in the blood before, and then after, consuming each food.

Why is it not beneficial to eat a lot of high GI foods? ›

Eating too much high GI foods causes repeated spikes in your blood glucose. Studies show that this can lead to an increased risk for type 2 diabetes, heart disease, obesity and colorectal cancer.

How does glycemic index affect weight loss? ›

How does Glycemic Index Affect Weight Loss? Studies have shown that after the insulin surge produced by consuming high GI foods, people tend to eat 60-70% more calories at their next meal. On the other hand, low Glycemic foods don't stimulate food-craving hormones that can trigger eating binges.

Does sugar affect glycemic index? ›

Some sugars actually have a low GI, as well as sugar containing foods like fruit, milk and yoghurt. Also, many starchy foods have a high GI. Rather than a focus on sugar alone, the GI value of all the carbohydrate in the food needs to be considered.
Sugar and the glycemic index.
SugarsGI value
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