Debunking the Myths: Why Do Some Say Oatmeal Is Not Healthy?

October 9, 2025 •

3 min read

According to the Food and Drug Administration, a daily intake of 3g or more of soluble oat beta-glucan can lower the risk of heart disease. However, widespread praise for this breakfast staple has not prevented some from asking: Why do some say oatmeal is not healthy?. This article investigates the critiques behind the debate.

Quick Summary

The reputation of oatmeal is challenged by several factors, including the high sugar content of instant varieties and the presence of antinutrients like phytic acid. Concerns also arise regarding potential gluten cross-contamination and the impact on blood sugar. The nutritional value is highly dependent on the type of oats and how they are prepared and served.

Key Points

Instant Oatmeal's Downsides: Many complaints about oatmeal's health come from heavily processed, sugar-laden instant packets, which can spike blood sugar.
Antinutrients are Overstated: While phytic acid in oats can hinder mineral absorption, this effect is minor in a balanced diet and can be reduced by soaking.
Processing Determines Glycemic Index: Less-processed steel-cut oats have a low glycemic index, while instant oats have a high one, impacting blood sugar differently.
Digestive Issues are Common but Manageable: The high fiber in oats can cause gas and bloating for newcomers, but starting with small portions and staying hydrated can help.
Context is Everything: The overall healthiness of oatmeal depends on the type chosen, portion size, and healthy additions like nuts, seeds, and fruits, rather than excessive sugar.
Health Benefits Outweigh Risks for Most: For the majority, the benefits of whole-grain oats—including heart health and gut support—far outweigh potential downsides when prepared properly.

For years, oatmeal has been championed as a wholesome breakfast choice, celebrated for its heart-healthy fiber and nutrient density. But a growing chorus of criticism suggests that this breakfast favorite may not be as healthy as once thought. The truth, as is often the case with nutrition, lies in the details. The perceived 'unhealthiness' of oatmeal is largely a matter of context, hinging on the type of oats, preparation methods, and individual health considerations.

The Concerns: A Closer Look at the Critiques Against Oatmeal

The Impact of Processing and Added Sugars

One significant reason for questioning oatmeal's health benefits is the processing of instant varieties. Unlike plain, whole oats, instant oatmeal is pre-cooked, dried, and cut, altering its nutritional profile and how quickly it's digested. Many instant packets contain substantial amounts of added sugar, artificial flavors, and preservatives, with some having up to 12 grams of added sugar per packet, potentially canceling out the whole grain's natural benefits. To make healthier choices, it's recommended to check ingredient lists and opt for less processed options like steel-cut or rolled oats.

Antinutrients: The Phytic Acid Debate

Oats contain phytic acid, an antinutrient that can bind to minerals like iron and zinc, potentially reducing their absorption. However, this is generally not a major concern for individuals with a balanced diet. Simple methods like soaking or cooking oats can help reduce phytic acid levels, ensuring you still benefit from the minerals.

Blood Sugar Spikes and Glycemic Index

Oatmeal's effect on blood sugar is another area of concern. Instant oats, due to their processing, have a high glycemic index (GI), leading to rapid blood sugar spikes. This is particularly relevant for those managing diabetes. In contrast, less processed steel-cut oats have a lower GI, resulting in a slower, more gradual rise in blood sugar. Choosing the right type of oats and managing portion size can help minimize blood sugar impact.

Digestive Issues and High Fiber Content

The soluble fiber in oats can cause gas and bloating in some individuals, especially those new to high-fiber diets. The beta-glucan fiber in oats can contribute to discomfort. Starting with small portions and gradually increasing intake, along with proper hydration, can help alleviate these temporary symptoms.

Potential for Contamination

While naturally gluten-free, oats can be cross-contaminated during processing in facilities that handle other grains. This is a significant concern for those with celiac disease, who should choose certified gluten-free oats. Additionally, a study identified the pesticide chlormequat in some oat products, raising further concerns, though the health implications are still being studied.

The Nutritional Truth: Why Oatmeal is Still a Health Powerhouse

Despite criticisms, less-processed oats offer significant nutritional benefits, including heart health due to beta-glucan fiber, blood sugar regulation, weight management, and essential vitamins and minerals. They also support gut health with prebiotic fibers and provide antioxidants.

A Comparison of Oat Types


Feature	Instant Oats	Rolled Oats	Steel-Cut Oats
Processing	Highly processed	Steamed and flattened	Least processed
Glycemic Index	High	Medium	Low
Cooking Time	Very fast	Quick	Long
Texture	Soft	Creamy	Chewy
Nutritional Impact	Can cause blood sugar spikes	Provides a steady energy release	Best for blood sugar control

How to Make Oatmeal a Truly Healthy Meal

To maximize benefits, choose plain, minimally processed oats. Soaking can reduce phytic acid and improve digestion. Add protein and healthy fats from nuts, seeds, nut butter, Greek yogurt, or protein powder. Use natural sweeteners like fruit or cinnamon. Savory options are also possible.

Conclusion: Context is Key

So, why do some say oatmeal is not healthy? Concerns stem from processing, added sugars, and digestive discomfort. However, dismissing all oatmeal is an oversimplification. The type and preparation significantly impact its value. By choosing less processed varieties and adding nutritious ingredients, oatmeal remains a healthy dietary component. This highlights the importance of context. Individuals with celiac disease must use certified gluten-free options.

Frequently Asked Questions

Instant oatmeal is more processed, giving it a higher glycemic index than rolled or steel-cut oats, which can cause a more rapid spike in blood sugar. This is a primary reason for concern, especially when coupled with added sugars.

Phytic acid is an 'antinutrient' in oats that can reduce the absorption of minerals like iron and zinc. However, the effect is not significant for most people with a varied diet, and soaking the oats overnight can help reduce its content.

While oats are naturally gluten-free, they are often cross-contaminated during processing in facilities that also handle gluten-containing grains. People with celiac disease must consume only oats that are certified as gluten-free.

The high soluble fiber content in oats can cause gas and bloating, particularly for those whose digestive systems are not used to a high-fiber diet.

To make oatmeal healthier, choose less-processed oats (steel-cut or rolled), limit added sugar by using fruits and spices, and boost the nutritional profile with healthy fats and protein from nuts, seeds, or Greek yogurt.

A study found detectable levels of the pesticide chlormequat in many oat-based products. While the health risks are still being evaluated, this is a concern for some consumers.

Yes, steel-cut oats are less processed, contain more fiber, and have a lower glycemic index than instant oats. This results in a slower, more stable release of energy and better blood sugar control.