Whole grains are healthy when eaten correctly, but eating them the wrong way can actually do more harm than good. It is true that whole grains contain more dietary fiber, B vitamins, and minerals than refined rice and white flour, but they are not a case of "the rougher, the better; the more, the better; or the mushier, the better." Many people who eat whole grains end up with problems such as blood sugar fluctuations, bloating, and acid reflux. Check how many of these common mistakes you are making.

Mistake 1: Treating whole grains as a "miracle cure for lowering blood sugar" and eating more and more of them

Whole grains cannot directly lower blood sugar. They have no pharmacological effect and cannot replace hypoglycemic drugs. Their main role is to slow down the rise of blood sugar, not to "bring it down." If you eat them for every meal and in large quantities just because you think they are healthy, you may end up consuming too many carbs, leading to excessive calorie intake.

The Chinese Dietary Guidelines (2022) recommend that adults consume 50–150 grams of whole grains and mixed beans, and 50–100 grams of tubers per day. Generally, whole grains can account for about one-quarter to one-half of staple foods; this is a reference value for healthy people, and patients with diabetes or digestive diseases should adjust the proportion under the guidance of a nutritionist. People with weak gastrointestinal function should proceed step by step, starting with small amounts, to avoid bloating and acid reflux.

Mistake 2: Grinding whole grains into powder and mixing them into a paste, thinking it is healthier

Many multigrain powders, five-grain pastes, and instant oatmeals seem convenient, but once whole grains are crushed, their complete physical structure is destroyed, and starch granules are directly exposed and more easily come into contact with digestive enzymes. Coupled with brewing with hot water or prolonged cooking, the degree of starch gelatinization increases, which may significantly accelerate the postprandial blood sugar rise.

For example, red beans have a low GI when boiled under normal pressure, but when baked, ground into powder, and mixed into a paste, their GI value may increase significantly; specific values vary depending on the variety, fineness of the powder, and brewing method. However, even if increased, the GI of pure bean multigrain paste is usually lower than that of white rice, but if sticky glutinous grains or refined grains are added to the recipe, the GI may not be low, and can even approach that of white rice, reducing the advantage of blood sugar control compared to cooking whole grains. After oats are made into a paste or instant oatmeal porridge, their GI usually increases significantly as well; if sugar and non-dairy creamer are added, the blood sugar control advantage will further decrease.

For those who want to control blood sugar and reduce fat, it is recommended to prioritize whole oats, brown rice, buckwheat, quinoa, etc., and cook them into multigrain rice or slightly firm multigrain porridge. When buying commercially available multigrain powders, also pay attention to checking the ingredient list.

Mistake 3: Only recognizing the words "whole grain" while ignoring stickiness and processing methods

Not all whole grains cause a slow rise in blood sugar. Sticky whole grains such as waxy corn, black glutinous rice, and proso millet have high amylopectin content, fast digestion speed, and significantly faster blood sugar rise than sweet corn, and are often higher than low-GI whole grains such as whole oats, barley, and mixed beans.

Tubers like sweet potatoes are often used as whole-grain staple foods to replace refined rice and white flour, but roasted sweet potatoes usually cause a faster blood sugar rise than steamed or boiled ones—because roasting reduces moisture and concentrates sugars, and at the suitable temperature of 60–70°C, the amylase in sweet potatoes converts some starch into small-molecule sugars such as maltose. Multiple factors lead to an increase in the proportion of free sugars and sugar concentration, resulting in a stronger blood sugar response. Steamed and boiled sweet potatoes are relatively more stable, but portion control is still necessary; you shouldn't eat more just because they are "whole grains."

In addition, whole wheat bread, whole grain biscuits, stuffed European bread, puffed multigrain crisps, etc., may contain a lot of added sugar, oil, or refined flour. When purchasing, check the ingredient list; whole wheat flour, oats, brown rice, etc., should be listed at the front, and try to choose products with less sugar, less oil, and fewer additives.

Mistake 4: The mushier the porridge is cooked, the better it is for the stomach

For people with sensitive gastrointestinal tracts, soft and mushy food is indeed easier to eat, but the longer and thicker whole grain porridge is cooked, the more complete the starch gelatinization, and the higher the postprandial blood sugar response usually is. If you just cook whole grains into a paste to "nourish the stomach," you may lose the advantage of blood sugar control and easily cause more obvious blood sugar fluctuations.

It should be noted that for those who have undergone gastrointestinal surgery, have poor teeth, or are extremely weak, easily digestible soft liquid food is required in the early stages of disease recovery, but this is usually low-fiber refined food, not high-fiber whole grain paste; long-term use of whole grain paste to "nourish the stomach" is even more undesirable.

More recommended practices are:

• Multigrain rice is more stable than multigrain porridge;
• Do not overcook porridge until it is mushy;
• When eating, pair with vegetables, eggs, soy products, lean meat, and other proteins and dietary fibers;
• Eat vegetables and protein first, then staple foods, which helps stabilize postprandial blood sugar.

How to eat whole grains more appropriately?

You can start with about one-quarter of your staple food and gradually increase it as your stomach and intestines adapt. Prioritize whole, minimally processed whole grains, and avoid grinding them into powder or mixing them into paste. Avoid excessive consumption of high-sugar, high-oil "pseudo-whole grains" and sticky whole grains. Combine coarse and fine grains, and eat them with vegetables and protein. People with weak gastrointestinal function, anemia, kidney disease, diabetes, or abnormal blood sugar should preferably adjust their diet under the guidance of a doctor or nutritionist. The type, amount, and cooking method of whole grains should be arranged individually. The truly healthy way of eating is not "only eating whole grains," but choosing the right type, controlling the amount, preserving the complete form, and pairing reasonably.