Which Flours Have the Highest Glycemic Index?

If you’re on a low-carb diet or otherwise are aware of the glycemic index of foods, you probably want to know which flours are the highest glycemic index. High glycemic index foods aren’t compatible with certain diets and lifestyles, including the keto diet.

Some of the flours with the highest glycemic indexes include:

• All-purpose flour
• Bread flour
• Cake flour
• Corn flour
• Fufu flour
• Instant flour
• Pastry flour
• Potato flour
• Rice flour
• Tapioca flour

In this article, we’ll explain more about what the glycemic index is, what impacts the glycemic index of flour, and review 10 high glycemic index flours.

What is the glycemic index?

The glycemic index (GI) is a measure of how much a single food affects your blood sugar levels. The scale for the glycemic index goes from 0-100, with pure glucose (the same type of sugar in your bloodstream) having a score of 100. 

Foods and drinks can be classified as low, medium, or high on the glycemic index scale. Here is how these categories are broken down:

Low GI: 0-55

Medium GI: 56-69

High GI: 70-100

Which factors impact the glycemic index in flour?

Flours high in starch and/or sugar tend to raise the glycemic index the most because they’re quickly broken down into glucose (blood sugar), which raises your blood sugar levels.

Things that can lower the glycemic index are fiber and fat. These nutrients take longer to digest than starch and sugar, which means the food will cause a more delayed rise in blood sugar levels compared to quickly-digested foods.

That means that low-fiber and low-fat flours that are also high in starch and sugars are the ones with the highest glycemic indexes, while those with the lowest starch and sugar (and high fiber and fat content) have the lowest glycemic indexes!

10 flours with the highest glycemic indexes

Below are ten flours with a glycemic index of 70 or greater, which means they are considered high on the glycemic index scale.

All-purpose flour (85)

All-purpose flour is considered “regular” flour and is the most common type of flour in most people’s pantries. All-purpose flour is refined, which means it strips the fiber- and protein-rich bran and germ from the wheat kernel, leaving behind the high-starch, low-fiber portion.

Bread flour (90)

Bread flour is higher in gluten and protein, which means it provides a chewy and elastic texture for making things like bread. Even though it’s higher in protein than some types of flour, it still has a high glycemic index of 90.

Cake flour (~85)

There isn’t a reliable source for the glycemic index for cake flour, but we can assume it’s high/similar to all-purpose flour since they have similar nutritional stats.

Cake flour is made from softer wheat, meaning it contains less gluten. Cake flour is suitable for making baked goods with a light, tender, and moist texture (low gluten=low chewiness).

Corn flour (70)

Corn flour is made from finely-ground corn kernels and is a popular gluten-free option for breading, as well as making cornbread.

It’s not surprising that corn flour has a high glycemic index since it’s made from corn, a starchy vegetable (starch is a carbohydrate that raises blood sugar levels).

Fufu flour (84)

What is fufu flour? It’s made from plantains, a tropical fruit, and sometimes also contains other flours like cassava and potato flour.

Fufu flour is popular in making African dishes. It’s typically gluten-free, but you should always check the ingredients label to ensure it doesn’t contain gluten-containing ingredients.

Instant flour (~85)

Instant flour likely has a high glycemic index similar to all-purpose flour. It’s flour that’s been pre-cooked and dried, which allows it to dissolve more quickly into liquids than regular flour. It’s typically a combination of wheat flour and malted barley flour. 

Pastry flour (~85)

Pastry flour is similar to cake flour but has a slightly higher protein/gluten content. While cake flour is best for making delicate cakes, pastry flour is ideal for making pie crusts, biscuits, muffins, and other pastries (baked goods that contain flour, water, and shortening). 

Potato flour (95)

Like corn, potatoes are a starchy vegetable. Starchy vegetables raise your blood sugar more quickly than non-starchy vegetables – and potato flour is no exception.

In fact, potato flour might be even higher on the glycemic index scale than some potatoes because it’s lower in fiber, while potatoes with the skins contain more fiber (5 grams of fiber per medium potato compared to 3 grams of fiber per ¼ cup of potato flour).

Rice flour (white rice) (88-95)

Rice flour doesn’t contain any fiber or fat, which raises its glycemic index compared to some flour that contains more fiber and fat.

Rice flour is a popular gluten-free flour and can be used to make baked goods, noodles, pizza crust, breading, and more. Rice flour can also be used as a thickener in sauces.

Tapioca flour (starch) (70)

Tapioca flour (also called tapioca starch) is derived from the cassava root, a plant native to Latin America. Tapioca flour is gluten- and corn-free (corn starch is among the most popular type of starches in cooking) and can be used in cooking, baking, and frying foods.

Tapioca flour doesn’t contain any fat, fiber, or protein, so consists primarily of starch – which makes it high GI.

Nutritional comparison of high glycemic index flours

-Serving size is ¼ cup

-GI scores with a ‘~’ means there isn’t a GI from a reputable source for that flour, but it can be estimated based on similar flours.

Flour	Calories	Total carbs	Fiber	Fat	Protein	Glycemic index
All-purpose flour	120	24 g	1 g	0.5 g	4 g	85
Bread flour	130	26 g	1 g	0.5 g	5 g	90
Cake flour	120	26 g	1 g	0 g	4 g	~85
Corn flour	120	24 g	3 g	1 g	2 g	70
Fufu flour	106	25 g	1.5 g	0 g	3.5 g	84
Instant flour	100	22 g	<1 g	0 g	3 g	~85
Pastry flour	120	26 g	1 g	0.5 g	3 g	~85
Potato flour	160	38 g	3 g	0 g	3 g	95
Rice flour	150	33 g	0 g	0 g	3 g	88-95
Tapioca flour	110	27 g	0 g	0 g	0 g	70

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