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Is corn bad for you? What about peas? They are vegetables, after all… These are some of the diet questions we find ourselves asking. And we're surely not the only ones.
Corn holds a great deal of nutritional value. It’s high in fiber, vitamins, and minerals but because it is derived from starch, it can also cause a spike in blood sugar and cause unwanted weight gain for some. And while you'll be hard-pressed to find a professional nutritionist who doesn't recommend eating more vegetables, their opinions, as well as studies about corn and its impact on diet and weight loss, have left many of us scratching our heads about whether it’s good or bad for us to eat.
A 2015 study conducted by researchers at the Harvard T.H. Chan School of Public Health examined the daily diets of approximately 130,000 adults over 20 years. Every four years, the scientists solicited food diaries of what participants had eaten every day for a week, and every two years, participants reported their exact weight. With these findings, the study was able to identify the impact that certain vegetables have on weight and blood sugar.
Does Corn Make You Gain Weight?
According to Harvard's report, participants who ate larger quantities of starchy vegetables, like corn, potatoes, and peas, were more likely to gain weight. Corn was the biggest culprit, with just over two pounds of weight gained for each additional serving spanning the four years. The reason? These starchy foods have higher glycemic loads, producing frequent, intense blood sugar spikes after they are eaten, which can ultimately make a person want to consume even more.
What Nutritionists Say
While Harvard is applauded for its top-notch professors and research teams, some nutritionists don't fully agree with this information. "I really don’t believe there is a 'worst' vegetable as long as it is sourced correctly," says NYC-based nutritionist Amy Shapiro, noting that it only becomes problematic when corn is the only vegetable as part of someone's diet. "Peas contain a fair amount of protein, potatoes are starchy and similar to corn except they contain different nutrients and are more digestible." She does, however, note that since these veggies are part of the nightshade family, they can be an issue for those with autoimmune issues. "Overall, these veggies can all play a role in a balanced diet as long as they are portion controlled and prepared in a healthy way," she says, noting to limit the common buttery and cheesy preparations of these foods.
Should You Cut Corn Out of Your Diet?
Mayo Clinic notes that corn has plenty of health benefits, containing B vitamins, as well as zinc, iron, and magnesium. It also serves a good source of antioxidants that support eye health such as lutein and zeaxanthin. However, the clinic does share that just ½ cup of the vegetable contains 15 grams of carbohydrate which is important for anyone who may be watching their carb and/or sugar intake.
Shapiro’s thoughts about corn consumption are quite similar. "I think corn can be part of a healthy diet since it contains many minerals and antioxidants that promote eye and skin health.,” she says. You can absolutely eat it daily, but I would consider it a starchier vegetable and would recommend limiting it to one ear of corn or 1/2 cup of corn kernels daily or at least per meal."
She also suggests only doing so during certain times of the year, as she reminds us that not all kernels are created equally. Shapiro says that "a lot of corn in the United States is genetically modified, as it is a cheap crop that is widely used to feed animals and to make inexpensive sweeteners." As such, she recommends saving corn for the summer, when you can eat it locally and fresh.
The Final Takeaway
While corn is delicious and can provide myriad health benefits, like most things, it should likely be consumed in moderation. In contrast to corn, the Harvard study found that participants who ate high-fiber vegetables, like kale and string beans, were likely to lose weight over time. As such, filling your plate with green and leafy veggies is a good place to start.
Bertoia ML, Mukamal KJ, Cahill LE, et al. Changes in intake of fruits and vegetables and weight change in United States men and women followed for up to 24 years: analysis from three prospective cohort studies. PLoS Med. 2015;12(9):e1001878. doi:10.1371/journal.pmed.1001878