Is Corn Good for Blood Sugar and Weight Loss?

Corn has a reputation for being too sweet and potentially even harmful to health. In reality, the golden kernels have several health benefits that can support stable blood sugar levels and weight loss.

a bowl of sweet corn with corn cobs in the background

Corn, first known as maize, has been a staple crop in North American agriculture for hundreds of years. It is drought resistant, easy to grow, and versatile in cooking. 

The main variety we consume is called sweet corn, and it offers a range of nutrients and fiber. This article will clear popular misconceptions about the health effects of corn and offer suggestions on how to include this popular vegetable into your diet.

Is Corn a Vegetable or a Grain?

Ripe corn is a starchy sweet tasting vegetable. It grows on the cob and is most popularly enjoyed grilled or boiled. You can also buy corn in the freezer section or in a can. 

Sometimes corn is harvested after ripening. It will lose the water content and become starchy, which is a precursor for flour. Powdered corn is light, usually yellow in color, and possesses the classic corn flavor. In this scenario, corn flour is considered a grain.

Do Americans Eat a Lot of Corn? 

Americans consume the largest amount of corn and corn by-products in the world.1In 2019 it was estimated that each person consumed 36.5lbs of corn products per year. This is a significant increase from data thirty years ago, which documented approximately 21lbs consumed per person. 

Corn products are easy to grow, economical for consumers, and taste good. It is a crop that has multiple uses so Americans end up eating quite a bit. 

While corn is a very popular vegetable, it’s not the most popular. The top two most popular vegetables that people consume are actually potatoes and tomatoes. We have articles on both of these vegetables and how they affect your blood sugars here. 

Different Types of Corn In America 

There are several different types of corn varieties grown in America, but here are the four major classes:2

  • Dent - field corn is used for feeding livestock and ethanol production.
  • Flint - colorful varieties of corn used for mealy foods including polenta. 
  • Pod - nonedible and used for ornamental purposes.
  • Sweet - the type of corn that is present at our dinner table. 

Sweet corn is the type of corn we eat. It’s rich in thiamin and phosphorus, and has moderate fiber content. The other varieties of corn not meant for human consumption. 

<p class="pro-tip"><strong>Learn more about </strong> <a href="/blog/fiber-for-metabolic-health">why fiber is so important for metabolic health</a>.</p>

How Does Corn Affect Blood Sugar?

Corn contains natural carbohydrates which are broken down into simple sugars during digestion. Sugars from food are absorbed into your bloodstream and can raise your blood sugar levels. 

Every person will have a unique glycemic response to corn. Some people may experience higher blood glucose levels and others may not. The only way to know how your body will respond is to use a continuous glucose monitor

Does Corn Spike Blood Sugar?

Corn alone may not cause your blood sugars to spike (it has a GI score below 55). But when you consider the full glycemic load of your meal, there is a good chance you may see a spike. It is very common to serve corn alongside other high-starch and high-carb foods, which all accumulate and can raise your blood sugar levels. 

Even though corn is a vegetable, it might be wise to treat it as a carb.  When you are building your dinner plate try to hold back on pairing corn with potatoes, bread rolls, and rice. Instead, add non-starchy vegetables to your plate like a fresh salad or stir-fried vegetables. 

<p class="pro-tip"><strong>Find a list of </strong> <a href="/blog/low-glycemic-vegetables">the top low-glycemic vegetables</a>.</p>

Does Frozen or Canned Corn Affect Your Blood Sugar Differently?

According to the glycemic index registrar, all versions of corn will have a similar GI score and will have a similar impact on your sugars when eaten alone. 

If you buy canned foods, remember to rinse them thoroughly before eating. Even if you don’t see a lot of liquid in the can, it is still recommended to properly wash your vegetables to rinse away residual sodium. 

a bowl of corn chowder
Homemade corn chowder can be part of a healthy weight-loss diet.

Glycemic Index of Corn

The GI of corn varies slightly based on the type of corn; the average range is between 77-82.3 This is a high GI score and tells us that there is a good chance corn will rapidly increase your blood sugar levels. 

How Corn Products Affect Blood Sugar

Below is a list of common corn-containing foods and how they influence your blood sugar: 

Corn Chips

Corn chips are similar to potato chips, but they are made with corn instead of potato. The recipe for corn chips varies per brand. On average, they have a glycemic index between 72-75 and are likely to increase your blood sugar levels. 

Corn Tortillas

Corn tortillas are similar to wheat-based tortillas, but they are made with corn flour. The flavor is more powerful and the texture is dense. They have a GI of 49-52, which is on the cusp between low and medium GI foods There’s a good chance corn tortillas will increase your blood sugars, especially if it is paired with a high GI food. 

Corn Meal

Corn meal is prepared as a porridge, used in pancake batter, or used to make cornbread. Corn meal has a glycemic index between 68-70. It is at the cusp of moderate to high GI, and it will likely increase your blood sugars.

Popcorn 

Popcorn is made by heating up corn kernels. It is a high-fiber snack option that can be nutritious as long as you don’t coat it with salt and butter. The glycemic index of popcorn is 55, so it’s unlikely to increase your blood sugars. 

High-Fructose Corn Syrup 

High fructose corn syrup (HFCS) contains fructose and glucose, whereas corn syrup only has glucose. HFCS has a GI of 56, and it may increase your blood sugars, especially if you consume several products throughout the day that have HFCS in the ingredients. 

Corn Starch

The starchy elements of raw kernels are ground and used to make cornstarch, an ingredient commonly used for thickening mixes. The glycemic index for cornstarch is 55-62. It is unlikely that corn starch alone will have an impact on your sugars, but if it is mixed with other high-carb foods (and it usually is) it can increase your blood sugar levels. 

Soluble Corn Fiber

Soluble corn fiber is made from corn starch. It is very difficult to digest in the body and few carbs are actually absorbed; therefore it has a low GI.4 It’s unlikely for soluble corn fiber to increase your blood sugar levels. 

<p class="pro-tip"><strong>Find a list of </strong> <a href="/blog/high-fiber-low-carb-foods">the best high-fiber low-carb foods for blood sugar</a>.</p>

6 tacos in hard shell corn tortillas seen from above
Corn tortillas have more fiber and fewer carbs than white flour tortillas.

Is Corn Good for Weight Loss?

Unprocessed versions of corn can be part of your weight loss journey. The bright juicy kernels are high in fiber and have a variety of minerals and vitamins

What you pair corn with will have a significant influence on the nutritional value. Try to pair corn with fresh, non-starchy vegetables, spices, and lean proteins: 

  • Fresh corn salad with red onion, tomatoes, and an olive oil dressing.
  • Grilled corn on the cob decorated with olive oil and your favorite seasoning blend. 
  • Add corn to vegetable soups or bean chili. 
  • Make the trendy cowboy caviar (mix together black beans, canned corn, red onion, avocado, jalapeno, cilantro, red wine vinegar, lime, honey, cumin, salt and pepper, garlic, and olive oil). 

Air-popped popcorn is also a high-fiber corn-based snack that can be decorated with different flavors. Instead of butter, try drizzling a teaspoon of olive oil and coating the popcorn with chili seasoning or garlic powder. 

<p class="pro-tip"><strong>Read more about </strong> <a href="/blog/snacking-and-weight-loss">snacking and weight loss</a>.</p>

How Often Should You Eat Corn? 

You can safely eat small amounts of corn every day, but leave room for other vegetables too. Making space in your daily meals to include other colorful vegetables will add greater diversity to your nutritional intake. 

Prioritize whole corn products whenever possible and keep your intake of refined corn products low, especially foods with high fructose corn syrup (HFCS). Too much of these high-sugar foods can increase your risk of diabetes, cardiovascular disease, and weight gain. 

Nutrition and Health Benefits of Corn

Corn offers a diverse range of nutrients including5

  • Vitamin C - an essential vitamin that supports your immune system, helps with collagen production, and protein synthesis. 
  • Potassium - an electrolyte involved with muscular signaling, regulating heartbeats, and fluid balance. 
  • Thiamin - a b-vitamin necessary for the growth, development, and function of cells.  
  • Fiber - a non-digestible carbohydrate that promotes satiety, slows down blood sugar uptake, lowers cholesterol, and reduces the chances of colon cancer. 

Although there are natural sugars in corn, there are many positive nutritional properties that make it a safe option to include in your diet. 

Potential Downsides of Corn

People who have irritable bowel syndrome (IBS) may be sensitive to corn because it is classified as a high FODMAP food. 

High FODMAP foods contain specific types of carbohydrates that can be difficult for people to digest. Common side effects include gas, bloating, diarrhea, and in some cases nausea.6

Regular studies are completed on the safety of consuming genetically modified corn products (GMOs).7Consistently the results all demonstrate that corn is safe to consume, with no adverse health effects linked to being a GMO. 

The FDA recommends limiting your intake of all processed foods, including corn-based products, for overall good health. 

<p class="pro-tip"><strong>Learn more about </strong> <a href="/blog/ultra-processed-foods">how ultra-processed foods affect blood sugar</a>.</p>

Corn, Blood Sugar, and Weight Loss: Takeaways

Fresh corn can affect your blood sugar, but you can decrease the potential blood sugar-raising effect by pairing it with protein-rich foods and healthy fats. Both of those macronutrients help to decrease the speed of digestion. 

Instead of pairing fresh corn with potatoes or other high-carb items, pair it with low carbohydrate options including other fresh vegetables. 

The FDA stated that small amounts of HFCS can be included in your diet, but your portion sizes should remain small.8 Eating too many products with HFCS can hinder your weight loss efforts. All sources of added sugars should be limited in your diet. 

<p class="pro-tip"><strong>Check out these </strong> <a href="/blog/5-low-glycemic-dinner-recipes">low-glycemic dinner recipes for busy weeknights</a>.</p>

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References

  1. USDA Economic Research Service. (2022, June 30). USDA ERS - Feedgrains Sector at a Glance. Feedgrains Sector at a Glance. Retrieved August 2022, from https://www.ers.usda.gov/topics/crops/corn-and-other-feedgrains/feedgrains-sector-at-a-glance/ 
  2. US Department of Agriculture. (2019, April). FoodData Central. Sweet Corn, Yellow. Retrieved August 2022, from https://fdc.nal.usda.gov/fdc-app.html#/food-details/169998/nutrients 
  3. University of Sydney. (n.d.). GI Search – Glycemic Index. Glycemic Index - Research and News. Retrieved August 2022, from https://glycemicindex.com/gi-search/?food_name=cornstarch&product_category=&country=&gi=&gi_filter=&serving_size_(g)=&serving_size_(g)_filter=&carbs_per_serve_(g)=&carbs_per_serve_(g)_filter=&gl=&gl_filter=
  4. Tan, W., Chia, P., Ponnalagu, S., Karnik, K., & Henry, C. J. (2020). The Role of Soluble Corn Fiber on Glycemic and Insulin Response. Nutrients, 12(4), 961. https://doi.org/10.3390/nu12040961 
  5. ​​Wu M, Cronin K, Crane JS. Biochemistry, Collagen Synthesis. [Updated 2021 Sep 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507709/ 
  6. Capili, B., Anastasi, J. K., & Chang, M. (2016). Addressing the Role of Food in Irritable Bowel Syndrome Symptom Management. The journal for nurse practitioners : JNP, 12(5), 324–329. https://doi.org/10.1016/j.nurpra.2015.12.007 
  7. Bawa, A. S., & Anilakumar, K. R. (2013). Genetically modified foods: safety, risks and public concerns-a review. Journal of food science and technology, 50(6), 1035–1046. https://doi.org/10.1007/s13197-012-0899-1 
  8. US FDA. (2018, January 4). High Fructose Corn Syrup Questions and Answers. High Fructose Corn Syrup Questions and Answers. Retrieved August 2022, from https://www.fda.gov/food/food-additives-petitions/high-fructose-corn-syrup-questions-and-answers

About the Author

Julia Zakrzewski Headshot
Julia Zakrzewski is a Registered Dietitian and nutrition writer. She has a background in primary care, clinical nutrition, and nutrition education. She has been practicing dietetics for four years.
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