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

Association between carbohydrate to protein or fat ratio and mortality: A prospective cohort study

BACKGROUND & AIMS

The effect of dietary macronutrient balance on longevity and metabolic health remains a subject of considerable interest. We aimed to investigate the association of carbohydrate-to-protein and carbohydrate-to-fat ratios with all-cause and cardiovascular mortalities.

METHODS

In this population-based study, data from the Korean Genome and Epidemiology Study were integrated with those from national data sources, including mortality records from the Korea National Statistical Office. The primary outcomes were all-cause and cardiovascular mortalities. Carbohydrate-to-protein and carbohydrate-to-fat ratios were evaluated based on dietary habits assessed through a food frequency questionnaire. Harrell's C-index was employed to determine optimal cut-off points for carbohydrate-to-protein and carbohydrate-to-fat ratios. Cox proportional hazards regression models were used to assess associations.

RESULTS

A total of 143,050 participants aged ≥40 years were included in the analyses. Compared with individuals with non-elevated carbohydrate-to-protein ratios (<5.2), those with elevated carbohydrate-to-protein ratios (>9.9) exhibited a higher all-cause mortality (hazard ratio 1.09, 95% confidence interval 1.01-1.17); however, no correlation between carbohydrate-to-protein ratio and cardiovascular mortality (hazard ratio 1.13, 95% confidence interval 0.96-1.32) was observed. Compared with those with non-elevated carbohydrate-to-fat ratios (<5.1), those with higher carbohydrate-to-fat ratios (>7.1) exhibited increased all-cause (hazard ratio 1.08, 95% confidence interval 1.00-1.16) and cardiovascular (hazard ratio 1.27, 95% confidence interval 1.06-1.52) mortalities.

CONCLUSIONS

Our findings regarding macronutrient ratios and their association with mortality suggest that reducing excessive carbohydrate intake and increasing the consumption of protein and fats may have beneficial effects on longevity and cardiovascular health. Further studies are needed to understand the underlying mechanisms of these effects.

Association of daily carbohydrate intake with intermuscular adipose tissue in Korean individuals with obesity: a cross-sectional study

BACKGROUND/OBJECTIVES

The prevalence of obesity, a worldwide pandemic, has been increasing steadily in Korea. Reports have shown that increased intermuscular adipose tissue (IMAT) is associated with an increased risk of cardiovascular disease, independent of body mass index. However, the relationship between dietary intake and IMAT accumulation in the Korean population remains undetermined. The objective of this study was to evaluate regional fat compartments using advanced magnetic resonance imaging (MRI) techniques. We also aimed to investigate the association between IMAT amounts and dietary intake, including carbohydrate intake, among Korean individuals with obesity.

SUBJECTS/METHODS

This cross-sectional study, performed at a medical center in South Korea, recruited 35 individuals with obesity (15 men and 20 women) and classified them into 2 groups according to sex. Anthropometry was performed, and body fat distribution was measured using MRI. Blood parameters, including glucose and lipid profiles, were analyzed using commercial kits. Linear regression analysis was used to test whether the IMAT was associated with daily carbohydrate intake.

RESULTS

Carbohydrate intake was positively associated with IMAT in all individuals, with adjustments for age, sex, height, and weight. No significant differences in blood indicators were found between the sexes.

CONCLUSIONS

Regardless of sex and age, higher carbohydrate intake was strongly correlated with greater IMAT accumulation. This suggests the need to better understand sex differences and high carbohydrate diet patterns in relation to the association between obesity and metabolic risk, which may help reduce obesity prevalence.

Efficacy of convenience meal-type foods designed for diabetes in the management of metabolic syndrome based on a 3-week trial

OBJECTIVES

This study aimed to assess the effect of meal-type food for diabetes on improving metabolic syndrome risk factors in adults.

METHODS

The participants were adult men and women aged 40-55 y with 1 or more risk factors for metabolic syndrome. They were provided with a diabetic diet (a meal-type food) and general diet in the form of home meal replacement for 3 wk. The current research used a crossover design. All participants had iso-caloric meal replacement per day, and there was a 2-wk washout period between each diet. The nutritional standards of a diabetic diet were based on the guidelines of the Ministry of Food and Drug Safety, which are: <50% carbohydrates, <10% sugars, <7% saturated fat, and >10 g dietary fiber. The average caloric content was 489.1 ± 45.0 kcal. The composition of the general diet was similar to that of the diabetic diet; however, there were differences in sugar content. In total, 15 participants were included in the research, and there was no significant difference between the 2 groups in terms of nutrient intake during the intervention period.

RESULTS

Body weight (P = 0.001), body mass index (P = 0.004), waist circumference (P = 0.030), triacylglycerol (P = 0.002), total cholesterol (P = 0.001), and low-density lipoprotein cholesterol (P = 0.008) levels were significantly lower in the diabetic diet intervention period than before and after 3 wk of the intervention. In addition, reduction in body weight (P = 0.001), body mass index (P = 0.006), waist circumference (P = 0.032), and triacylglycerol (P = 0.036) and total cholesterol (P = 0.007) levels in the diabetic diet intervention period significantly differed compared with those in the general diet intervention period.

CONCLUSIONS

Replacing 1 meal per day with meal-type food for diabetes improved body composition and blood lipid levels in adults with metabolic syndrome risk factors.

Non-pharmacologic treatment for obesity

Background: The prevalence of obesity has been rapidly increasing in the Korean population. Obesity is a well-known risk factor for various chronic diseases, including diabetes mellitus, hypertension, dyslipidemia, atherosclerosis, chronic kidney disease, degenerative arthritis, and autoimmune diseases. It also increases the risks of different malignancies, gall bladder disease, and pancreatitis.Current Concepts: Lifestyle intervention assisted by frequent behavioral therapy is crucial despite the modest amount of weight loss achieved. Energy intake restriction combined with increased physical activity can not only facilitate weight loss but also improve metabolic health. Furthermore, this combination can help maintain weight reduction during and after lifestyle interventions. Energy intake restriction with a daily deficit of 500–1,000 kcal and physical activity including aerobic exercise for 150 minutes or more per week and resistance training 2–4 times a week are generally recommended for obesity management.Discussion and Conclusion: Comprehensive lifestyle intervention should be individualized and supported by a multidisciplinary team. A long-term behavioral intervention is necessary for success in obesity treatment.

Current status of obesity treatment in Korea: based on the 2020 Korean Society for the Study of Obesity guidelines for obesity management

Background: Obesity is a complex disease, and its prevalence is gradually increasing globally. The increasing prevalence of obesity is shown to significantly affect the development of obesity-related comorbidities. This paper describes the recent updates on obesity treatment in Korea based on the 2020 Korean Society for the Study of Obesity guidelines for obesity management.Current Concepts: Accurate evaluation of obesity is important before treatment initiation. Obesity in Korean adults is defined as body mass index ≥25 kg/m2, and abdominal obesity is defined as waist circumference ≥90 cm for men and ≥85 cm for women. It is recommended that energy intake be reduced and that the degree of energy restriction be individualized based on patient characteristics and medical conditions. Guidelines recommend assessment of the exercise participation and health status before prescribing exercise therapy; aerobic exercise for at least 150 min/week or 3–5 times/week is advised to facilitate weight loss. Although nutrition and behavior therapy and increased physical activity constitute the mainstay of obesity treatment, pharmacotherapy is recommended concomitant with comprehensive lifestyle modification. Bariatric surgery should be actively considered in patients with severe obesity and in those with obesity-related comorbidities.Discussion and Conclusion: Obesity and the associated comorbidities result in an increased socioeconomic and medical burden. Multifactorial intervention using a team approach is warranted for optimal management of obesity. This guideline will benefit primary care physicians for safe and effective decision-making regarding obesity management and treatment.

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

Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations. A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled trials (RCTs) of carbohydrate-restricted diets and 10 articles on eight RCTs of IF was performed. Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes mellitus, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension. Here, we describe the results of our analysis and the evidence for these recommendations.

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

BACKGROUND

Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations.

METHODS

A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled clinical trials (RCTs) of carbohydrate-restricted diets and ten articles on eight RCTs of IF was performed.

RESULTS

Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension.

CONCLUSION

Here, we describe the results of our analysis and the evidence for these recommendations.

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

Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations. A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled trials (RCTs) of carbohydrate-restricted diets and 10 articles on eight RCTs of IF was performed. Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes mellitus, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension. Here, we describe the results of our analysis and the evidence for these recommendations.