Protein & Fat Delay Estimator
Estimate how much protein and fat in a meal will delay your blood glucose peak - and whether a secondary "pizza effect" rise is likely.
Educational estimator only - not medical advice.
0-300g
0-200g
0-200g
This calculator estimates the delay and pattern of blood glucose rise based on protein and fat content. The delay formula is:
When fat content exceeds 30g, gastric emptying is significantly slowed, creating the "pizza effect" - a secondary glucose rise at 3-5 hours after eating. This is particularly important for insulin users who dose before meals.
Fat slows the rate at which food moves from the stomach to the small intestine (gastric emptying), blunting the initial carbohydrate spike but extending glucose elevation for hours.
Protein is partially converted to glucose through gluconeogenesis (roughly 50% of excess protein over several hours), creating a slow, extended glucose rise. This effect is most significant for people with type 1 who dose precisely for carbs only.
Chapter 4 of the FOD Mature Series explores the pizza/pasta effect in detail - the science of how mixed meals affect glucose, practical strategies for insulin timing, and what CGM data reveals about individual responses.
FOD Mature Series - Ch. 4This calculator provides estimated values based on population averages. Individual responses to food vary considerably. Always test your personal response with a CGM or blood glucose meter. Do not adjust insulin doses based solely on this calculator - consult your diabetes care team.