Low-Carbohydrate Diets in Korea: Why Does It Matter, and What Is Next?

Abstract

In recent years, low-carbohydrate diets have become highly popular in Korea as a means to lose weight. People following this regime believe that fat and protein can be consumed in unlimited quantities, as long as carbohydrate intake is strictly restricted. However, low-carbohydrate diets are more complex than simply reducing carbohydrate intake. Meta-analyses of randomized clinical trials revealed that low-carb diets are at least as effective as low-fat diets in terms of weight loss, but their cardiovascular effects vary. Low-carbohydrate diets confer more beneficial effects on weight loss and lipid profiles such as triglycerides and high-density lipoprotein cholesterol but exhibited detrimental effects on lipid profiles such as total and low-density lipoprotein. Korean diets are typically high in carbohydrates, where carbohydrate intake is in the range of 50%-80% of total energy. Within this range of carbohydrate intake, high carbohydrate intake was associated with an increased risk of elevated triglyceride and high-density lipoprotein-cholesterol levels but with a reduced risk of elevated total and low-density lipoprotein-cholesterol levels. The optimal range of carbohydrate intake was depicted by a U-shaped relationship between carbohydrate intake and mortality, with 50%-60% of energy from carbohydrates having the lowest mortality risk. The distribution of macronutrients varied greatly according to age and sex groups in Korea. There is no single diet that can be recommended to all individuals, especially if focusing only on the quantity of macronutrients as opposed to their quality. The health benefits of low-carbohydrate or low-fat diets may depend on the source of protein and fat and the carbohydrate quality.

Effect of Carbohydrate-Restricted Diets and Intermittent Fasting on Obesity, Type 2 Diabetes Mellitus, and Hypertension Management: Consensus Statement of the Korean Society for the Study of Obesity, Korean Diabetes Association, and Korean Society of Hypertension

“…In most clinical studies, carbohydrate-restricted diets are classified as moderately-low carbohydrate diets (MCD) with carbohydrates accounting for 26% to 45% of total caloric intake, low carbohydrate diets (LCD) with carbohydrates accounting for 10% to 25%, and very-low carbohydrate diets (VLCD) with carbohydrates accounting for less than 10% [92]. Considering that the average carbohydrate intake rate is about 65% in South Korea, which is significantly higher than that of other countries, and that the greater the restriction, the lower the adherence [93]. Thus, we evaluated MCD and LCD as a combined category, moderately-low carbohydrate or low carbohydrate diets (mLCD) (Supplementary Table 5).…”

Effect of carbohydrate-restricted diets and intermittent fasting on obesity, type 2 diabetes mellitus, and hypertension management: consensus statement of the Korean Society for the Study of obesity, Korean Diabetes Association, and Korean Society of Hypertension

“…In most clinical studies, carbohydrate-restricted diets are classified as moderately-low carbohydrate diets (MCD) with carbohydrates accounting for 26–45% of total caloric intake, low carbohydrate diets (LCD) with carbohydrates accounting for 10–25%, and very-low carbohydrate diets (VLCD) with carbohydrates accounting for less than 10% [ 92 ]. Considering that the average carbohydrate intake rate is about 65% in South Korea, which is significantly higher than that of other countries, and that the greater the restriction, the lower the adherence [ 93 ]. Thus, we evaluated MCD and LCD as a combined category, moderately-low carbohydrate or low carbohydrate diets (mLCD) (Additional file 1 : Supplementary Table 5).…”

“…Furthermore, well-designed RCTs in Korean patients are also needed. Considering that the carbohydrate intake rate of Koreans is about 65%, which is significantly higher than that of other countries [ 93 ], future studies must evaluate 1) whether this benefit can be maintained even after adjusting the carbohydrate restriction rate to 45 ~ 55%, which is higher than that of MCD, and 2) whether carbohydrate restriction to the level of MCD or LCD would be harmful to Koreans.…”

Effect of Carbohydrate-Restricted Diets and Intermittent Fasting on Obesity, Type 2 Diabetes Mellitus, and Hypertension Management: Consensus Statement of the Korean Society for the Study of Obesity, Korean Diabetes Association, and Korean Society of Hypertension

“… 92 Considering that the average carbohydrate intake rate is about 65% in South Korea, which is significantly higher than that of other countries, and that the greater the restriction, the lower the adherence. 93 Thus, we evaluated MCD and LCD as a combined category, moderately-low carbohydrate or low carbohydrate diets (mLCD) ( Supplementary Table 5 ). IF includes several different dietary regimens, such as time-restricted feeding, alternate-day fasting, and intermittent energy restriction, as well as those with similar meanings.…”

“…Furthermore, well-designed RCTs in Korean patients are also needed. Considering that the carbohydrate intake rate of Koreans is about 65%, which is significantly higher than that of other countries, 93 future studies must evaluate…”