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Side Effects of Eating Too Much Oatmeal, According to Experts

Is there really such a thing as too much oatmeal? We spoke with doctors and dietitians to find out the truth.

Don't get us wrong—oatmeal truly is one of the healthiest breakfast foods you can eat. In fact, oatmeal is proven to be the best breakfast for a longer life. However, while oatmeal is full of numerous health benefits—like having a good amount of healthy dietary fiber—eating too much oatmeal can create some negative side effects to one's body. This is why we turned to doctors and dietitians to find out what happens to your body when you end up eating too much oatmeal at once.

Here's what the experts had to say, and for more healthy eating tips, be sure to check out our list of The 7 Healthiest Foods to Eat Right Now.

You could significantly increase your sugar intake.

bowl of oatmeal with nut butter fruit and chocolate chips

"People typically want their oatmeal to be sweeter so as not to eat a boring meal," says Dr. Gan Eng Cern. "They achieve this by adding sugar, chocolate chips, and other sweet food items which ultimately decreases oatmeal's overall nutritional value as these additions throw in extra calories, fat, sugar, carbs."

In particular, make sure to steer clear of The Unhealthiest Oatmeals On The Planet.

You're limiting your nutritional palate.

High fiber breakfast whole grain oatmeal with fresh berries nuts and seeds

"Although daily oatmeal breakfasts can provide you with all the energy and nutrition you need to jump-start your day, eating these everyday imposes restrictions on the variety of healthy foods you can eat in the morning," says Dr. Eng Cern. "Basically, you're depriving your body of being nourished by other healthy food—you're limiting your own palate which makes you miss out on all other tasty food that can give you as much nutrition and energy."

Here's What Happens To Your Body When You Eat Oatmeal.

It can lead to malnutrition and muscle mass shedding.

man holding bowl of oatmeal

"Although oatmeal helps promote weight loss by suppressing your appetite, too much of it can lead to malnutrition and muscle mass shedding," says Dr. Eng Cern. "This is because oatmeals keep you fuller for longer, so you often lose your body's ability to signal you to eat more throughout the day. Eating almost nothing but oatmeal can also interfere with your cognitive functions and diminish your alertness and sharpness."

This is why it's important to get a variety of nutritional foods into your diet—especially these 25 Healthy Foods That Give You Glowing Skin.

It can cause bloating.

Oatmeal with berries

Because of the fiber content in oatmeal, the digestion process may cause some bloating for a person—especially if you're not used to eating oatmeal on a regular basis.

"If you are new to oats, they may cause bloating so it's best to start with a small portion," says Lisa Young, PhD, RDN, and author of Finally Full, Finally Slim.

"Whole grains such as wheat and oats contain high fiber, glucose, and starch," says Shannon Henry, RD for EZCare Clinic. "All of them are consumed by bacteria in the gut or large intestine which leads to gas and bloating in a few people. To lessen the side effects, start with a small quantity and increase gradually to the chosen amount. When you will start eating oat bran, the harmful outcomes from your body will probably disappear."

If you're eating larger portions of oatmeal at a time, you may experience bloating from the higher amount of fiber in your system. Instead, portion out your oatmeal when you eat it for breakfast, and to make it filling, add some of these 11 Healthy Oatmeal Toppings That Help You Lose Weight.

It can lead to weight gain.

Oatmeal blueberry

"Eating a jumbo serving of oatmeal can lead to weight gain," says Young. "And watch the toppings—a tablespoon or two of crushed walnuts or flaxseeds is great but too much butter or sugar isn't."

So if you're looking to stay slim, be sure to read up on these 6 Oatmeal Mistakes Making You Fat.

Kiersten Hickman
Kiersten Hickman is a freelance health and nutrition journalist. Read more about Kiersten
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