Prediabetes: Epidemiology, diagnosis, and management

Table 3 Effects of dietary interventions relevant to prediabetes on body weight, glycemic control, blood lipids, and sustainability

Diet	Key features	Body weight	Blood lipids			Blood glucose	HbA1c	Sustainability
			HDL-C	LDL-C	Triglycerides
Ketogenic diet	High-fat, very low-carbohydrate pattern; macronutrient composition varies, and classical regimens are often approximately 70% fat, 10% carbohydrate, and 20% protein[120]	Usually decreases in overweight/obese adults and in T2DM studies; evidence specifically in prediabetes remains limited[49,50,53,54]	Variable; may increase in some studies[53,54]	Variable; LDL-C may increase in some individuals and should be monitored[49,120]	Usually decreases[49,53,54]	May improve fasting or overall glycemia, mainly supported by T2DM and mixed dysglycemia studies[49,53,54]	May decrease in the short term; in Keto-Med, HbA1c reduction was not clearly superior to Mediterranean diet[49]	Restrictive pattern; long-term adherence may be challenging and may be lower than with the Mediterranean diet[49,51]
Mediterranean diet	Plant-based dietary pattern emphasizing vegetables, fruits, whole grains, legumes, nuts, olive oil as the main fat source, moderate fish intake, and limited saturated fat[57,121]	May support weight loss or weight maintenance when combined with energy control and lifestyle management[71,121,122]	May improve or maintain HDL-C[122]	Generally neutral or favorable, depending on baseline diet and fat quality[121-123]	May decrease[121,122]	Associated with improved glycemic control and lower diabetes risk in clinical and epidemiological studies[59,60,71,121-124]	May decrease; benefits are reported in T2DM and prediabetes-related studies[49,121,122]	Generally more compatible with long-term dietary practice than highly restrictive regimens[49,71]
PPT diet	Personalized postprandial glucose response-targeting diet based on individual-level data and machine-learning prediction[70]	Not primarily a weight-loss diet; modest decrease reported in some intervention studies without prescribed calorie restriction[72]	May improve, but evidence is limited and not consistently superior to Mediterranean diet[71,72]	No consistent advantage over Mediterranean diet has been established[71,72]	May decrease, but evidence remains limited[71,72]	Targets postprandial excursions; one prediabetes trial showed better reduction in postprandial hyperglycemia than Mediterranean diet[71]	Greater HbA1c reduction than Mediterranean diet was reported in one prediabetes trial[71]	Personalization may support adherence, but implementation depends on data collection, algorithm access, and patient engagement[70,71]

HDL-C: High-density lipoprotein cholesterol; LDL-C: Low-density lipoprotein cholesterol; HbA1c: Glycated hemoglobin; PPT: Personalized postprandial glucose response-targeting diet; T2DM: Type 2 diabetes mellitus.