Flour can be made from grinding any grain. White flour from wheat uses all of the wheat kernel. In white flour, only the starchy part is used. Refined flour is missing nutrients found in whole wheat flour. White flour is an added ingredient in many processed foods.
Most people usually like their wheat grains ground up forming bread, cereal and crackers, etc. Regular whole wheat bread has a GI in the high sixties, which is considered high. White bread is rated even higher in the mid seventies.
The fiber content of food tends to lower its GI. The more cooked or processed the food, the higher the GI, but not always. What nobody wants are highs and lows in blood sugar over a long period of time. This can cause health issues bringing damage to the body in the form of kidney failure, strokes, heart attacks, also raising the risk of obesity and diabetes.
Fiber only comes from plants. Fiber comes in two types. Soluble fiber can help lower glucose levels (sugar) and lower cholesterol. Insoluble fiber which cannot dissolve in water, promotes regularity and helps prevent constipation.
Grains have low nutrient content and don’t taste good plain. White flour is usually fortified. Salt, sugar and spices have to be added to make refined grain products palatable.
Resistant starch (carbohydrate) slows sugar absorption. It is present in plant based whole foods such as lentils, beans, unripe bananas, rolled oats, fruits and potatoes. They resist digestion in the small intestine passing into the large intestine where fermentation as a result of friendly bacteria produce enzymes which break down the resistant starches.
Therefore, the better choice (instead of white flour) is plant based whole food like beans, vegetables, legumes, fruit, brown rice and potatoes. I replaced bread with brown rice and potatoes. Refined flour in snack foods like crackers digests quickly making blood sugar rise too fast which can turn to fat stored in your body.