Low-calorie Diet in Isolated Impaired Fasting Glucose

Inclusion Criteria: 1. Aged 35 to 65 years 2. Overweight (body mass index (BMI) ≥25 to \<29 kg/m² or ≥23 to \<29 kg/m² if Asian descent) or Obese (BMI ≥30 kg/m²) 3. Physically inactive (\<150 minutes per week of moderate-intensity physical activity or \<75 minutes per week of vigorous-intensity physical activity) 4. Prediabetes diagnosis or score ≥5 on the American Diabetes Association (ADA) risk tool Exclusion Criteria: 1. Diagnosed with type 1 or type 2 diabetes 2. Cardiovascular disease (myocardial infarction, stroke, angina, heart failure, or other cardiac conditions) 3. Chronic kidney disease 4. Chronic liver disease (e.g., cirrhosis) 5. Cancers 6. Acute inflammatory bowel disease, irritable bowel syndrome, celiac disease, chronic pancreatitis, or other disorders potentially causing malabsorption 7. Food allergies 8. Participation in weight loss programs in the past six months 9. Currently following a specific diet (e.g., ketogenic diet, Mediterranean diet) 10. Participation in any exercise programs in the past six months 11. Currently taking weight-loss medications or drugs known to affect glycemia (steroids and antipsychotics) 12. Previous bariatric surgery or plan to have bariatric surgery during the study period 13. Planning to relocate during the study period 14. Intending to fast during the study period for religious or other reasons 15. Pregnancy or planning to become pregnant during the study period 16. Breastfeeding 17. Non-English speaker