U.S. nutrition experts have pointed to sharp swings in blood sugar — so-called blood sugar spikes — as the reason many people feel drowsy after dinner.
Dolores Woods and Amanda Sauceda, both registered dietitians in the United States, said in a recent interview with the health publication Verywell Health that dinner menus high in refined carbohydrates and sugar trigger excessive insulin secretion followed by a steep drop in blood sugar, according to medical sources on the 8th. The two identified white bread, noodles made from regular wheat flour and sugar-sweetened beverages as foods to avoid, and recommended whole-grain bread, whole-grain noodles and unsweetened drinks as alternatives.
Korean data points in a similar direction. According to the Korean Diabetes Association, the prevalence of diabetes among adults aged 30 and older stood at 14.8% in 2022, while 40% of the same age group were classified as prediabetic. That translates to roughly 14 million people. A separate survey put the prediabetic population at about 15.83 million, close to 40% of the total population. The more frequent the swings in blood sugar, the greater the likelihood of progressing from prediabetes to diabetes.
Refined grain products are a prime concern. The refined grains used in white bread and bagels convert directly into glucose during digestion, pushing blood sugar higher, and are relatively low in nutrients such as fiber. Woods advised choosing 100% whole-grain products when buying bread. Fiber in whole-grain bread slows the breakdown of carbohydrates and the absorption of glucose, flattening the rise in blood sugar.
Noodle dishes made with refined flour, such as instant ramyeon and pasta, warrant the same caution. They appear often on dinner tables because they are easy to prepare, but the burden on blood sugar is no different from that of white bread. Whole-grain noodles made from brown rice or quinoa contain fiber and complex carbohydrates that slow digestion and reduce the effect on blood sugar. Sauceda said adding mashed beans to pasta sauce is another option, explaining that the complex carbohydrates in legumes break down slowly in the body and help control blood sugar.
Sugar-sweetened beverages are also on the list. Sodas, sports drinks and fruit juices all affect blood sugar. A study published in the international journal Journal of Nutrition, which tracked more than 3,000 middle-aged men and women for 14 years, found that those who consumed sugar-sweetened beverages faced a higher risk of increased insulin resistance and prediabetes than those who drank diet soda. Woods said sugar-sweetened drinks contain simple sugars in high concentrations that raise blood sugar quickly and sharply, and suggested lemon water or unsweetened tea as alternatives.
Cutting back on carbohydrates, however, is not the same as eliminating them. Carbohydrates are a primary source of energy for the body, and the key is balance with other nutrients such as protein. Sauceda noted that the problem is not carbohydrates themselves but a dinner plate weighted toward them. She added that consuming at least 20 grams of protein alongside carbohydrates can keep blood sugar more stable.
