Refined Grains, Insulin Resistance and Type 2 Diabetes

Flour is hard to avoid during meal times. Breakfast options mainly consist of toast, bagels, cereal, and pancakes. A convenient lunch is sandwiches, wraps, pasta or pizza. Dinner might come with its own temptations too. As a result, the average American now eats 10 servings of refined grains each day. What effect do these refined grains have on your health? Do consuming refined grains predispose you to Type 2 Diabetes? In this article, we will have a look at factors that could put you at risk.

  1. What Is the Difference Between Whole Grains and Refined Grains?

While whole grains are very high in dietary fiber, refined grains are much lower in fiber and micronutrients.

Whole grains consist of three main parts:

  1. Bran: The hard outer layer, containing fiber, minerals and
  2. Germ: The nutrient-rich core, containing carbs, fat, protein, vitamins, minerals, antioxidants and plant compounds.
  3. Endosperm: The middle layer, containing mostly carbs and small amounts of protein.

The bran and germ are the most nutritious parts of whole grains. They contain high amounts of many nutrients, such as fiber, B vitamins, iron, magnesium, phosphorus, manganese, and selenium.

During the refining process, the bran and germ are removed, along with all the nutrients they contain. Removing the nutrients from the grain has implications. On the upside, it makes things like bread doughy and spongy — textures we like and have come to crave. On the downside, the nutritional value of the food is severely compromised, and these striped grain products actually deplete our body’s reserves of important vitamins and minerals.

The nutrient content of refined flour is determined by the ‘extraction rate’ (the proportion of the grain retained after milling). Refined flour produced in Australia is milled to an extraction rate of 78-80% resulting in higher nutrient content (prior to fortification) than flour produced in countries using a lower extraction rate (e.g. 73-75% in the USA).

This leaves almost no fiber, vitamins or minerals in the refined grains. What’s left is rapidly digested starch with small amounts of protein.

  1. What are the effects of consuming refined grains on our health?
  • Blood sugar spikes: Because flour is easily digestible, it causes our blood sugar to spike, which could lead to a rise in insulin. The pancreas has to crank out a lot of insulin to metabolize the glucose in flour-rich foods, which can set the body up for insulin resistance, diabetes, and bodywide inflammation.Refined grains have a higher glycemic index, which is how quickly the body turns food into fuel or glucose.  A carbohydrate in wheat, called amylopectin A, is more easily converted to blood sugar than most other carbohydrates. Two slices of bread made with whole-wheat flour could raise blood sugar higher than six teaspoons of table sugar and higher than many candy bars.
  • Overeating and ObesityObesity is the leading factor in Insulin resistance, Type 2 diabetes, and other chronic diseases. Eating too many refined carbs may be one of the main culprits. As they are low in fiber and digested quickly, eating refined carbs can cause major swings in blood sugar levels. This can contribute to overeating.
  • As we have discussed above, foods high on the glycemic index promote short-term fullness, lasting about one hour. On the other hand, foods that are low on the glycemic index promote a sustained feeling of fullness, which lasts about two to three Blood sugar levels drop about an hour or two after eating a meal high in refined carbs. This promotes hunger and stimulates parts of the brain associated with reward and craving.
  • These signals make you crave more food, and are known to cause overeating. This constant eating leads to obesity, a pre-diabetic state, and eventual diabetes.
  • Slower Metabolism: Research shows that the body may shift nutrients into fat storage and away from muscle burning in the presence of high-glycemic-index foods. In 2004, Ludwig and his colleagues at Harvard conducted a study, published in the journal Lancet, in which they fed rats diets with identical nutrients, except for the type of starch. By the end of the study, rats in both groups weighed roughly the same, but those eating a high-glycemic diet had 71 percent more fat than the low-glycemic-index group.
  • Inflammation: A diet high in grains stokes inflammation. When blood sugar spikes, glucose builds up in the blood. When glucose drifts in the blood, it could attach itself to nearby proteins. The result is a chemical reaction called glycation, a pro-inflammatory process that plays a role in a host of inflammatory diseases — everything from Type 2 diabetes to arthritis to heart disease.
  • GI Disorders: Studies show that the lectins in grains inflame the lining of the gut and create fissures between cells. Also, when whole-kernel grains are refined, 80 percent of the fiber is lost, and gut health suffers. Without the fiber, you end up with rapid-release carbs in these grains, which is a bad thing for the gut. Fiber helps sweep the gut of debris and supports the body’s critically important elimination and detoxification processes, which also play a role in keeping high cholesterol and inflammation at bay.
  • Food Allergies/Intolerances: Wheat, in particular, is one of the biggest dietary triggers of food allergies and intolerances. While the exact reason is unclear, many experts blame the higher gluten content of modern wheat varieties. A type of protein found in many grains, including wheat, gluten gives dough elasticity, trapping air bubbles and creating a soft texture. Because soft is considered desirable, wheat today is bred to have more gluten than ever before.
  • Acid-Alkaline Imbalance: The body has an elaborate system of checks and balances to keep its pH level at a steady 7.4. A diet high in acidic foods, such as grains, forces the body to pull calcium from the bones to keep things on an even keel. When researchers looked at how the diets of more than 500 women affected their bone density, they found that a diet high in refined grains, among other nutrient-poor foods, was linked to bone loss. A highly acidic diet also chips away at our cellular vitality and immunity in ways that can make us vulnerable to chronic disease. Grains are the only plant foods that generate acidic byproducts. Wheat, in particular, is among the most potent sources of sulfuric acid, a powerful substance that quickly overcomes the neutralizing effects of alkaline bases.
  1. How can we have grains in their most healthy form?

Whole grains deliver fiber, healthy fats, vitamins, minerals, plant enzymes and hundreds of phytochemicals. For those seeking a dense source of carbohydrate energy, they can be a healthy choice — but only if they are unrefined and minimally processed. Here are a few steps toward upgrading your own grain options:

  • Choose whole-kernel grains when possible.
  • Try sprouted grains.
  • While baking, replace part of the flour with nut or seed meals.
  • Stick with truly whole-grain flours.
  • Don’t overdose on gluten-free foods.
  • Try going flour-free.
  • Consider a grain sabbatical.
  1. Are refined grains a culprit in Insulin resistance and Type 2 Diabetes?

When ground into flours, most grains act like sugar in the body, triggering weight gain, inflammation, and blood-sugar imbalances. Studies show that high consumption of refined carbs is linked with insulin resistance and high blood sugar levels. These are some of the main symptoms of type 2 diabetes.

Refined carbs also increase blood triglyceride levels. This is a risk factor for both heart disease and type 2 diabetes. It is therefore advisable to keep our refined grain consumption at a minimum and if we do indulge, check that what we are having is fortified.


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  1. NCBI (2002): Effect of whole grains on insulin sensitivity in overweight hyperinsulinemic adults. Retrieved from
  1. Popsugar (2019): 4 Reasons to Eat Whole Grains Instead of Refined. Retrieved from
  1. Healthline (2017): Why Refined Carbs Are Bad For You. Retrieved from
  1. Experience Life (2019): The Truth about Refined Grains. Retrieved from

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