Refined grains are a problem because milling strips out the bran and germ. What is left is fast-digesting starch with almost no fiber, vitamins or minerals. That starch spikes blood sugar and insulin and drives overeating. It is tied to more belly fat, heart disease and type 2 diabetes.
Wheat is the key ingredient in the American diet. Sadly, after milling, it is rarely eaten whole with all its parts intact. We eat our wheat as bread, pies, cakes, cookies, biscuits, spaghetti, cream of wheat, cereals, and more. All of these have been treated, heated, split apart, and broken up. Is eating refined grains harmful? Here is the answer.
- What are refined grains?
Almost every nutrition expert agrees that refined carbs should be limited. We go further: refined grains should be cut out. Yet they are still the main source of dietary carbs in many countries.
What Are Refined Carbs?
Refined carbs are also known as simple carbs or processed carbs.
There are two main types:
- Sugars: Refined and processed sugars, such as sucrose (table sugar), high fructose corn syrup, and agave syrup.
- Refined grains: These are grains that have had the fiber-rich, nutritious parts taken out. The biggest source is white flour made from refined wheat.
Refined carbs have been stripped of almost all fiber, vitamins, and minerals. That is why they can be called “empty” calories. They lead to rapid spikes in blood sugar and insulin.
They are also digested fast and have a high glycemic index (a measure of how fast a food raises blood sugar). This means they cause rapid spikes in blood sugar and insulin after meals. Eating foods high on the glycemic index has been linked to overeating and a higher risk of many diseases.
Sadly, sugars and refined grains make up a very large part of total carb intake in many countries. The main sources of refined carbs are white flour, white bread, white rice, pastries, sodas, snacks, pasta, sweets, breakfast cereals, and added sugars. They are also added to all sorts of processed foods.
How do grains get refined?
Whole grains consist of three main parts;
- Bran: The hard outer layer containing fiber, minerals, and antioxidants.
- Germ: The nutrient-rich core containing carbs, fat, protein, vitamins, minerals, antioxidants, and plant compounds.
- Endosperm: The middle layer contains mostly carbs and small amounts of protein.
The bran and germ are the most nutritious parts of whole grains. They hold high amounts of many nutrients, such as fiber, B vitamins, iron, magnesium, phosphorus, manganese, and selenium.
Refining removes the bran and germ, along with all the nutrients they hold. This leaves almost no fiber, vitamins, or minerals in refined grains. The only thing left is fast-digesting starch with small amounts of protein. Whole grains are very high in dietary fiber.
Some producers add synthetic vitamins to their products to make up for some of the lost nutrients. People have long debated whether synthetic vitamins are as good as natural ones. But most people agree that getting your nutrients from whole foods is always the best choice.
Diets high in refined carbs also tend to be low in fiber. Low-fiber diets have been linked with a higher risk of diseases like heart disease, obesity, type 2 diabetes, colon cancer, and various digestive problems.
- The Effect of refined grains on your health
Abdominal Fat – Eating mainly refined grains may increase your visceral adipose tissue (VAT). This is a type of fat found around your organs that may in time lead to diabetes and heart disease. In one study, people who ate at least three servings of whole grains per day had approximately 10 percent less VAT than people who ate only refined grains.
Overeating and Increase the Risk of Obesity- A large share of people are overweight or obese. Eating too many refined carbs may be one of the main culprits. They are low in fiber and digested fast. So eating refined carbs can cause major swings in blood sugar. This can add to overeating. This is because foods high on the glycemic index give short-term fullness, lasting about one hour. Foods low on the glycemic index give a lasting feeling of fullness, about two to three hours.
Heart Health-Eating refined grains instead of whole grains may result in atherosclerosis, or thickening of the arteries. That is a risk factor for heart disease. Another study found that the bran part of whole grains may be the most protective against heart disease. Refined grains no longer have it. In that study, participants who ate the most added bran had the lowest risk of heart disease.
Diabetes-People who eat fewer whole grains and more refined grains have a higher risk of diabetes. Studies show that eating a lot of refined carbs is linked with insulin resistance (when cells stop answering insulin) and high blood sugar. These are some of the main symptoms of type 2 diabetes. This may be partly due to the lower fiber, magnesium, and vitamin E in refined-grain foods. These nutrients drop when whole grains are refined.
Mortality-Fiber from whole grains may protect against early death. The same is not true of fiber from refined grains. The fiber in refined grains comes from the endosperm of the grain, which holds few nutrients. The fiber in whole grains also includes fiber from the bran and germ, which are richer in nutrients. The benefits of whole grains may be due to more than the fiber they contain.
- Why are refined grain products harmful?
Refined grains and their food products are substandard foods for several reasons:
- They are excessively starchy and high in gluten.
- They are practically devoid of natural fiber.
- There can be up to approximately 25 different chemicals that are added to refined grains and bread products.
- Grains are fumigated.
- Bleaching chemicals are used.
- Artificial colorings and flavorings are used.
- They are nutritionally imbalanced.
- Because refined grain products are nutritionally out of balance, they help cause several degenerative diseases (diseases where tissue breaks down over time). Calcium leaches from the bones and teeth because these products throw off the phosphorus-calcium balance. Sugar and refined grain products are the main cause of tooth decay in this country. They are also the major cause of brittle bones in the elderly.
- What are some Gluten-Free Grain Alternatives?
- Amaranth
- Buckwheat
- Corn
- Millet
- Quinoa
- Rice
- Wild Rice
- To take, or not to take, refined grains?
In the US, the familiar white flour, which comes from the modern refining process, is 72% extraction. This means it has lost 28% of the bulk of the wheat, including half or more of many of the key nutrients. Cut refined flour products out of your diet.
Eating a lot of refined carbs can have many harmful health effects. But not all carbs are bad. Some carb-rich, whole foods are very healthy. They are great sources of fiber, vitamins, minerals, and helpful plant compounds. Some healthy carb-rich foods include vegetables, fruit, legumes, and root vegetables. Grains are not on that list: gluten and gliadin drive leaky gut and autoimmune problems in chronic pain. Unless you are following a carb-restricted diet, there is absolutely NO reason to avoid these foods just because they contain carbs.
Related reading
- Refined Grains: Are They Bad for You?
- Are Refined Grains Bad for You?
- Refined Grains vs Whole Grains
References
- Healthline (2017): Refined Carbs Are Bad For You. Retrieved from https://www.healthline.com/nutrition/why-refined-carbs-are-bad#section1
- SF Gate (2018): The Health Side Effects of Refined Grains. Retrieved from https://healthyeating.sfgate.com/health-side-effects-refined-grains-3064.html
- NCBI (2019): Perspective: Refined Grains and Health: Genuine Risk, or Guilt by Association? Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520038/
- Food Matters (2011): Why Refined Grains Are Harmful + 8 Gluten-Free Whole Grain Alternatives. Retrieved from https://www.foodmatters.com/article/why-refined-grains-are-harmful
- Sott (2019): Why Refined Grains Are Harmful. Retrieved from https://www.sott.net/article/226260-Why-Refined-Grains-Are-Harmful
Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed June 18, 2026
