Although there are all kinds of diets in the world, it is difficult to adhere to all diets while keeping health in mind. LCD and Mediterranean diets are well-known for adequate type for diabetes [1,2], but Effects of the Dietary Approach to Stop Hypertension (DASH) diet and Nordic diets have also been proposed [3,4]. As a group of the European Association for the Study of Diabetes (EASD), Diabetes and Nutrition Study Group (DNSG) has summarized and provided evidence-based guidelines to health professionals [5]. When analyzing enormous data, they use the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. Important messages include i) minimum processed plant food which are whole grains, whole fruit, vegetables, ii) decreasing sugar-sweetened beverages, refined grains, sodium, red and processed meats. ?

There are three meals a day, and breakfast is the one that is least affected by the social environment and personal life. Recently, there has been a study that examined the effect of using low carbohydrate diet (LCD) or calorie Restriction (CR) breakfast on blood glucose control [6]. Two types of breakfast were provided to 121 patients with type 2 diabetes (T2D), average age 64, for 12 weeks and compared. For its content, LCD had 8g of carbohydrates 8g and 465kcal, and CR had carbohydrate 56g and 450kcal. The decrease in HbA1c was -0.3% for the former and -0.1% for the latter, a difference of -0.2%. The difference in self-reported total daily energy was -242kcal (p=0.03) and -73g carbohydrate, p<0.01.

From these results, the noteworthy fact would be the influence of CR for breakfast. Between LCD and CR, no difference was found for intake of dinner and snacks, but the energy intake of lunch is higher in CR breakfast. Consequently, total daily energy intake also increased in CR breakfast group. The reason would be due to the changes in post-prandial glucose. For LCD breakfast, blood glucose does not rise. In contrast, CR breakfast raises blood glucose rapidly and it will decrease after the peak. From the obtained data of questionnaire, CR breakfast results in elevated sense of hunger feeling before lunch. Actually, the values of breadth or speed of decreasing blood glucose before lunch may bring strong hunger sensation, much appetite and increased meal intake [7].

In this study, 8,624 standardized meals were consumed and analyzed [7]. The results showed the following successive process. They are?i) a decrease in blood glucose about 2-3 hours after meal, ii) an increase in hunger for 2-3 hours, iii) a reduction in the time until the next meal, iv) an increase in energy intake in 3-4 hours, and v) an increase in energy intake in 24 hours. These data showed all significant difference (all p<0.001). Consequently, this would be an distinctive evidence that suggests a relationship among changes in postprandial blood glucose, changes in appetite and energy intake [8].

Concerning the relationship among diet, appetite, and obesity, big meals at dinner have been attracting attention so far [9]. From this report, however, it has become clear that differences in hunger and food intake are significantly influenced by the amount of carbohydrates in breakfast. In other words, paying a little attention to breakfast can affect several markers such as amount of food eaten throughout the day, total calorie intake, body weight, and HbA1c. Thus, it is meaningful to pay attention to the carbohydrate content of breakfast, which may influence clinical progress of patients with diabetes, obesity and life style-related diseases.

For adequate treatment for diabetes, and metabolic syndrome, authors and collaborators have continued diabetic clinical studies in LCD and CR for years [10,11]. The patients were type 1, 2 diabetes (T1D, T2D), slowly progressive insulin-dependent diabetes mellitus (SPIDDM), and lifestyle-related diseases [10,12]. Among our research investigation, we have proposed novel C-peptide index for Carbohydrate-70 (CPI-Carbo70) test for analyzing the glucose variability [11]. It can use usually Japanese style breakfast including 70g of carbohydrate. The protocol included 37 T2D cases with average HbA1c 8.1% and median Morbus (M) value 70.5. The results showed the values of 0 vs 30min as 163 mg/dL vs 195mg/dL, 1.1 vs 1.5μU/mL, respectively. Thus, CPI-Carbo70 revealed 1.94 in average and 1.54 in median. Significant negative correlation was found between HbA1c and CPI-Carbo70, that showed y = -0.2479x + 0.217, R² = 0.2019. Thus, CPI-Carbo70 seemed to be useful for indication insulin secretion and resistance situation in diabetic patients. Furthermore, our CPI-Carbo70 study showed advanced method. T2D cases (n=46) were divided into 3 groups, which were HbA1c 6.6%, 7.8%, 10.0%, respectively [13]. Increase of CP and CPI-Carbo70 revealed 0.58, 0.57, 0.27 and 2.1, 3.2, 1.2, respectively. Several factors may be involved in these results. Consequently, CPI-Carbo70 may be effective for evaluating glucose variability and pancreas function, leading to future research development.

As to CPI-Carbo70, Japanese style breakfast has been originally applied. Furthermore, western style breakfast has been also developed. Two types of breakfast are shown in Figure 1, in which carbohydrate amount is 4.2g and 69.7g, respectively.

Figure 1: breakfast samples with carbo amount.

In summary, LCD has been one of the dietary measures with a history of over 100 years [14]. It has been actually applied to patients with diabetes and also convulsions for long associated with recognition of clinical effects [15]. Therefore, preclinical studies for its safety would be not required. Although some opinions are concerned about the long-term safety of LCD, no adverse events due to persistent LCD or elevated ketone levels have not been reported. In other words, it is not meaningful to examine negative phenomena using animal experiments such as rodents. Less carbohydrate amount in breakfast contributes less post-prandial blood glucose elevation. Consequently, this article will hopefully become a useful reference for clinical diabetic research in the future.

Conflict of interest: The authors declare no conflict of interest.

Funding: There was no funding received for this paper.

1. Evert AB, Dennison M, Gardner CD, Garvey WT, Lau KHK, MacLeod J, et al. Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report. Diabetes Care. 2019; 42: 731-754.
2. Davies MJ, Aroda VR, Collins BS, Gabbay RA, Green J, Maruthur NM, et al. Management of hyperglycaemia in type 2 diabetes, 2022. A consensus report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetologia. 2022; 65: 1925-1966.
3. Davies MJ, D'Alessio DA, Fradkin J, Kernan WN, Mathieu C, Mingrone G, et al. Management of Hyperglycemia in Type 2 Diabetes, 2018. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care. 2018; 41: 2669-2701.
4. Vasei MH, Hosseinpour-Niazi S, Ainy E, Mirmiran P. Effect of dietary approaches to stop hypertension (DASH) diet, high in animal or plant protein on cardiometabolic risk factors in obese metabolic syndrome patients: A randomized clinical trial. Prim Care Diabetes. 2022; 16: 634-639.
5. Diabetes and Nutrition Study Group (DNSG) of the European Association for the Study of Diabetes (EASD). Evidence-based European recommendations for the dietary management of diabetes. Diabetologia. 2023; 66: 965-985.
6. Oliveira BF, Chang CR, Oetsch K, Falkenhain K, Crampton K, Stork M, et al. Impact of a Low-Carbohydrate Compared with Low-Fat Breakfast on Blood Glucose Control in Type 2 Diabetes: A Randomized Trial. Am J Clin Nutr. 2023; 118: 209-217.
7. Wyatt P, Berry SE, Finlayson G, O'Driscoll R, Hadjigeorgiou G, Drew DA, et al. Postprandial glycaemic dips predict appetite and energy intake in healthy individuals. Nat Metab. 2021; 3: 523-529.
8. Yang K, Yang Y, Xie Y, Mao Y, Li X, Guo Q. Impact of macronutrient composition in nutrition shakes on postprandial glycemic response, appetite, and food intake. Food Hydrocolloids 2023; 141: 108685.
9. Longo-Silva G, de Oliveira Lima M, Pedrosa AKP, Serenini R, de Menezes Marinho P, de Menezes RCE. Association of largest meal timing and eating frequency with body mass index and obesity. Clinical Nutrition ESPEN. 2024; 60: 179-186.
10. Ebe K, Bando H, Yamamoto K, Bando M, Yonei Y. Daily carbohydrate intake correlates with HbA1c in low carbohydrate diet (LCD). J Diabetol. 2018; 1: 4-9.
11. Bando H, Ebe K, Bando M and Yonei Y. Index of C-peptide / glucose ratio for Carbo70 can be useful in clinical practice for diabetes. J Clin Invest Stud. 2018; 1: 1-4.
12. Wood M, Ebe K, Bando H. Honeymoon Phase by the effect of Low Carbohydrate Diet (LCD) after onset of Type I Diabetes (T1D). Int J Endocrinol Diabetes. 2023; 6: 158.
13. Ebe K, Bando H, Muneta T, Bando M, Yonei Y. Investigation of C-peptide Index for Carbo70 by the severity of diabetic state. Clin Med Case Rep. 2018; 2: 113.
14. Osler W, McCrae T. The principles and practice of medicine, 8th ed. New York, London, D. Appleton and company. 1915; 436-439.
15. Lennerz BS, Koutnik AP, Azova S, Wolfsdorf JI, Ludwig DS. Carbohydrate restriction for diabetes: rediscovering centuries-old wisdom. J Clin Invest. 2021; 131: e142246.