Corn get a bad rap in many different health and diet communities. The keto and low-carb crowd says it’s a refined carbohydrate that will spike insulin and lead to blood sugar issues. The paleo guys avoid corn because it’s a Neolithic grain which most ancestral populations (except for some in the New World) never had access to. Carnivore and autoimmune diet folks worry about the anti nutrients corn might contain, which can trigger gut issues and lead to nutrient loss. Even conventional “healthy diet” people generally recommend against eating corn when so many “better” options exist.
Is this criticism warranted? Is it true that corn has no place in a healthy diet, or is corn actually healthy? How does corn fit into a Primal diet?
Let’s dig into the actual evidence.
Every civilization who evolved with corn as a staple food used a process called nixtamalization—the soaking and cooking of corn in an alkaline solution before processing for consumption. The Incans of South America, the Aztec and Maya of Central America and Mexico, and various North American populations all developed some form of nixtamalization. Some used lime water, others used wood ashes. But they all did it. Doing so breaks down the cellulose in corn, turns the oil into an emulsifying agent, and allows the proteins and carbohydrates to bond to each other. Nixtamalized corn can form a dough, whereas untreated corn cannot. But there are other benefits, too.
When the Spanish came to the Americas, they found civilizations thriving with a bizarre new grain as the staple food. It was called corn and it was delicious: nutty, sweet, starchy. They brought it back to Europe where it quickly spread across the continent, owing to its adaptability, but people who used it there as a staple often developed a serious disease called pellagra, or niacin deficiency. Without nixtamalization, the niacin found in corn is bound to the cellulose and inaccessible to humans who eat it. The nixtamalization process frees the niacin so we can absorb it, breaks down some of the phytic acid, and increases levels of other vitamins. It also adds some calcium to the corn. This is why any product made with nixtamalized cornmeal, or masa, will have a decent amount of calcium in the nutrition facts. In fact, that’s one way to know if the corn product you’re considering is nixtamalized; check the calcium content.
Even if you unlock the nutrients in corn with proper preparation, it’s not the most nutrient-dense food around. A half cup of masa harina, which is nixtamalized corn flour used to make tortillas and other traditional corn staples, is decent but not mind-blowing:
Conventional corn is one of the most heavily sprayed crops in the entire country. Both sweet corn (the kind you eat fresh) and grain corn (the kind that’s turned into cornmeal or masa) are frequently sprayed with both Roundup (glyphosate) and atrazine. Hell, corn is often engineered to be “Roundup-ready,” meaning it can handle huge doses of Roundup while still thriving.
Both Roundup and atrazine should be avoided whenever possible. Roundup is even more toxic to gut bacteria than isolated glyphosate, and atrazine has been shown to feminize male frogs and reduce androgen levels.1 These effects likely cross species, so don’t think it’s limited to amphibians.
The occasional conventional tortilla or ear of corn is fine and I wouldn’t stress, but the more corn you eat, the more you should try to get organic corn.
The reason why corn was paired with beans as a staple food in most pre-contact American diets is that neither beans nor corn are complete protein sources. They are complementary, meaning they provide the amino acids the other is missing. Nixtamalized corn combined with beans acts as a legitimate staple diet in some traditional groups, in fact, like with the Tarahumara people of Mexico, providing all the RDAs for nutrients.2
The easiest way to ensure you’re getting enough protein is to eat meat, seafood, and other animal protein with your corn. I don’t recommend a corn and legume-based diet unless you’re really committed to avoiding meat.
Yes, corn is a grain. But it’s one of the least offensive grains around:
All in all, corn is technically a grain but it doesn’t always act like one. The issues that cause us to avoid grains like wheat aren’t present in corn.
Since corn is a grain, and grains don’t like to be eaten by predators, corn does contain anti-nutrients—compounds designed to dissuade consumption and damage the health of bacteria, insects, and critters who try to eat it. However, basic preparation methods are quite good at mitigating the effects of corn anti-nutrients.
The primary anti nutrient in corn is phytic acid, which can reduce mineral absorption, but it’s pretty easy to deplete with basic preparation.
Corn is a starch, and starches are high in carbohydrates. That makes them off limits for most ketogenic diets. But if you’re doing a cyclical ketogenic diet (where you stray from keto for short periods of time), or a targeted ketogenic diet (where you consume carbs in and around hard workout sessions), or doing targeted carb refeeds (where you eat carbs once or twice every 7-10 days to refill glycogen stores and restore leptin levels), you can probably fit some in without destroying your progress.
Here are the carb counts for some common corn-based foods. You can decide when and where they fit into your diet.
Two corn tortillas: 21 grams carbs, 3 grams fiber, 104 calories
A cup of sweet corn: 23 grams carbs, 3 grams fiber, 110 calories
Two cups of popcorn (popped): 12.4 grams carbs, 2 grams fiber, 62 calories
A half cup of masa harina (nixtamalized corn flour): 44 grams carbs, 3.6 grams fiber, 207 calories
The beauty of a corn tortilla is not in the corn or the tortilla. It’s in what it allows you to eat. You can get a single corn tortilla that’s roughly 10 grams of carbs and pile it thick and high with carne asada, chopped onions, avocado, and melted cheese. That becomes a very protein-rich and nutrient-dense meal for fewer carbs than you’d think.
Corn can be an inoffensive addition to a Primal diet. I wouldn’t make it a staple or large source of calories—much better options exist—but corn can be included if you like it and tolerate it. If you do decide to eat corn, keep these basic guidelines in mind:
Do you eat corn? How do you like it best?
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