Overwhelmed by Sleepiness After Lunch? Refined Grains May Be Controlling Your Blood Glucose

The drowsiness that pours in after lunch, known as postprandial somnolence, may not simply be caused by a lack of sleep. It is closely related to a blood sugar spike. The carbohydrates we consume are broken down into glucose through digestion, and when this glucose is absorbed into the bloodstream, blood glucose rises. In particular, refined carbohydrates such as white rice, white bread, and sugary beverages are digested and absorbed very quickly, causing blood glucose to surge rapidly. When blood glucose rises sharply, our body excessively secretes insulin from the pancreas to lower it. Insulin quickly pushes glucose from the blood into cells to be used as an energy source or stored as fat, but this sudden excess secretion of insulin results in blood glucose dropping too rapidly. The phenomena that appear at this time are symptoms similar to hypoglycemia: fatigue, drowsiness, impaired concentration, and lethargy. The brain uses glucose as its primary energy source, and when blood glucose drops sharply, sufficient energy is not supplied to the brain, leading to the experience of brain fog. When these blood sugar spikes are repeated, cells easily develop insulin resistance, where they become desensitized to insulin. Insulin resistance strains the pancreas even more, forcing it to secrete more insulin, and eventually weakens pancreatic function, raising the risk of progressing to type 2 diabetes mellitus. In addition, blood sugar spikes and excessive insulin secretion become primary causes of metabolic syndrome—including abdominal obesity, hypertension, and hyperlipidemia—and can contribute to an overall decline in health by triggering chronic inflammation. Please remember that this is not an issue to simply dismiss as postprandial somnolence, but can be a signal threatening your overall metabolic health. The fiber in whole grains or vegetables slows the absorption rate of glucose to buffer blood sugar spikes, and protein and fat maintain satiety for a long time, providing tremendous help for healthy eating habits.