Both cornstarch and flour are common ingredients used in cooking and baking. But is one healthier than the other? There are some key differences between cornstarch and flour that impact their nutritional value.
What is Cornstarch?
Cornstarch is a fine, powdery starch made from corn kernels. To make cornstarch, corn kernels are first soaked in water to soften them. Then, the corn goes through a wet milling process to separate the starch from the protein and fiber. The starch is then dried to produce the final cornstarch powder.
Cornstarch is composed almost entirely of carbohydrates. A 2 tablespoon serving of cornstarch contains:
- 24 grams of carbohydrates
- 88 calories
- 0 grams of fat
- 0 grams of protein
- 0 grams of fiber
This makes cornstarch a high glycemic index food, meaning it is digested and absorbed quickly, leading to a spike in blood sugar.
What is Flour?
Flour is a powder made from grinding grains, seeds, nuts, legumes or tubers. The most common types of flour are made from wheat, but flours can also be made from other ingredients like rye, corn, rice, oats, barley, buckwheat, quinoa, amaranth and more.
Unlike pure starch like cornstarch, flour contains carbohydrates along with protein, fat and fiber:
- Carbohydrates: Most flours are around 70-75% carbohydrates by weight.
- Protein: Flour contains gluten forming proteins like gliadin and glutenin. The protein content ranges from 7-15% based on the flour type.
- Fat: Whole grain flours contain around 2% fat from the germ portion of the grain. White flours have the germ removed and contain very little fat.
- Fiber: Fiber ranges from 2-4% in refined white flours to 8-15% in high fiber whole grain flours.
Due to their protein and fiber, most flours have a lower glycemic index than pure starch like cornstarch.
Key Nutritional Differences
Here is an overview of the key nutritional differences between cornstarch and all-purpose flour:
| Nutrient | Cornstarch | All-Purpose Flour |
|---|---|---|
| Calories | 88 per 2 tbsp | 160 per 1/4 cup |
| Carbohydrates | 24g per 2 tbsp | 28g per 1/4 cup |
| Protein | 0g | 3g |
| Fat | 0g | 1g |
| Fiber | 0g | 1g |
As this comparison shows:
- Cornstarch is 100% carbohydrates, while flour has a mix of carbs, protein, fat and fiber.
- Cornstarch has more calories and carbs by volume compared to flour.
- Flour contains gluten protein, while cornstarch has no protein.
- Flour has a small amount of fat, while cornstarch has none.
- Flour has some fiber, but cornstarch is fiber-free.
Blood Sugar Impact
The biggest difference between cornstarch and flour is the effect on blood sugar levels. Let’s compare how they impact blood sugar:
- Cornstarch: Has a very high glycemic index of 85. It breaks down quickly and causes a rapid spike in blood sugar.
- All-Purpose Flour: Has a glycemic index of 75, which is still fairly high. The protein and fiber content help slow digestion somewhat.
- Whole Wheat Flour: Has a glycemic index of 55, which is considered low. The higher fiber and protein reduce the blood sugar impact.
For controlling blood sugar, whole grain flours are healthier choices than refined flours, which are healthier than pure starches like cornstarch.
Nutritional Pros and Cons
Here is a summary of the key nutritional advantages and disadvantages of cornstarch versus flour:
Cornstarch Pros
- Gluten-free: Cornstarch is naturally gluten-free.
- Versatile thickener: It can thicken sauces, gravies, puddings and more.
- Smooth texture: Adds gloss and sheen in cooking applications.
Cornstarch Cons
- Rapidly spikes blood sugar levels.
- Nutritionally empty: Contains no protein, fat, fiber or micronutrients.
- Less baking utility: Does not contain gluten needed for structure in baked goods.
Flour Pros
- Good source of carbohydrates: Provides carbohydrates for energy.
- Gluten protein provides structure: Allows breads and baked goods to rise.
- More balanced nutrition: Contains some protein, fat and fiber.
- Lower glycemic impact: Less of a blood sugar spike compared to pure starch.
Flour Cons
- Higher calorie: More calories per gram than pure starch.
- Allergy risk: Wheat/gluten flours trigger allergies for some.
- Less thickening power: Not as good at thickening foods as cornstarch.
Cornstarch vs. Flour for Health Conditions
Due to their differing nutritional profiles, cornstarch and flour may be better suited for some health conditions compared to others:
Diabetes
For diabetes, whole grain flours like whole wheat or buckwheat are healthier choices than cornstarch or refined flours. The fiber content helps slow carbohydrate absorption and prevent spikes in blood sugar levels. Avoid cornstarch as it causes rapid spikes in blood glucose.
Celiac Disease
For celiac disease or gluten sensitivity, cornstarch is the better option. Since it’s naturally gluten-free, cornstarch won’t trigger adverse reactions compared to gluten-containing wheat flour.
Food Allergies
Cornstarch may be the safer choice for those with wheat or grain allergies. Flours made from gluten-free grains, nuts or legumes can also be used.
Heart Health
Whole grain flours can contribute to heart health as part of an overall healthy diet. The fiber content helps reduce cholesterol levels. Soluble fiber may also help lower blood pressure. Cornstarch in moderation is fine, but excessive amounts can spike blood sugar which is unhealthy for the heart.
Weight Loss
For weight loss, flour may be a slightly better choice due to its higher protein and fiber content. The protein and fiber help you feel fuller for longer after eating. But for the most part, both cornstarch and flour should be used in moderation on a diet.
Cooking Uses
Due to their different properties, cornstarch and flour are used in some similar and some differing ways in cooking:
Thickening Agent
Both cornstarch and flour can thicken liquids like sauces, gravies and pie fillings. However, cornstarch results in a glossier, more translucent final product. Flour has more of a matte, opaque effect. Cornstarch also thickens at a lower temperature compared to flour.
Baked Goods
Flour is better suited for baking uses like breads, cakes, cookies due to its gluten content. Gluten allows dough to stretch and capture gas released during baking for a light and airy texture. Using only cornstarch can result in dense, tough baked goods. However, small amounts of cornstarch combined with flour can enhance the texture.
Frying
Cornstarch is commonly used to coat foods before frying to get a crispy exterior. It can help fried foods stay crispy longer after cooking. Flour is also used in frying applications, but imparts a different texture.
Sauces
Both flours and cornstarch are used as thickeners in savory sauces and gravies. Cornstarch gives a glossy, translucent finish. Flour has a more opaque appearance. Combining the two can provide the best texture in certain sauces.
Fillings
In sweet pie fillings and pastry cream, cornstarch helps prevent syneresis or weeping of liquid. It gives a rich, thick texture. Flour tends to settle out in fillings over time.
Storing and Substituting Cornstarch and Flour
Storage
Cornstarch and flour should be stored in airtight containers in a cool, dry location. Whole grain flours have a shorter shelf life than refined flours and cornstarch due to their higher oil content. Cornstarch and flours may clump if exposed to moisture.
Substitution
Cornstarch and flour cannot be substituted 1:1 in recipes due to their different properties. However, here are some substitution guidelines:
- For thickening liquids: Substitute 2 tablespoons cornstarch for 1 tablespoon flour
- For frying: Substitute up to half the flour for cornstarch for a crisper texture
- For baking: Substitute up to 1/4 the flour for cornstarch to enhance texture
For the best results, look up specific substitution ratios for individual recipes rather than substituting randomly.
The Bottom Line
So in the end, is cornstarch healthier than flour? Here’s the bottom line:
- Cornstarch is 100% carbohydrate starch, while flour also provides some protein, fat and fiber.
- Cornstarch results in faster blood sugar spikes compared to flour.
- Flour contains gluten, which cornstarch does not.
- Whole grain flours like whole wheat have the lowest glycemic impact.
- For health, whole grain flours are best. Cornstarch is fine in moderation.
- Cornstarch gives superior thickening and crisping texture. Flour performs better in baked goods.
The healthiest choice depends on your specific nutrition needs and recipe. But both cornstarch and flour can have their place in healthy cooking when used properly.
