Normal pre-meal target: 80-130 mg/dL

Enter your pre-meal BG, carbs, GI, and macros above to predict your glucose spike.

This predictor uses a macronutrient-adjusted model combining Glycemic Load with the moderating effects of protein, fat, and fiber on glucose absorption:

GL = (GI x Carbs) / 100
Spike = (GL x 1.5) - (Fiber x 0.5) - (Protein x 0.2) - (Fat x 0.15)
Peak BG = Pre-meal BG + Spike

Protein slows gastric emptying and stimulates insulin secretion, reducing the glucose spike. Fat significantly delays digestion - a high-fat meal can push peak BG 2-4 hours later. Fiber directly slows carbohydrate absorption and reduces postprandial spikes.

Time to peak: Low-GI or high-fat/protein meals peak at 60-90 min; high-GI, low-fat meals at 30-45 min. These are approximations - individual responses vary. Always calibrate with your own CGM data.

! Medical Disclaimer
This calculator is for educational purposes only. Predictions are approximations based on population averages. Individual glucose responses vary widely based on insulin sensitivity, medications, stress, activity, and gut health. Always consult your healthcare provider or certified diabetes educator before making changes to your management plan.