Warsaw Method Calculator
HealthEstimate fat-protein units (FPU) and extended-bolus insulin dosing guidance for high-fat, high-protein meals using the Warsaw method. Educational tool only.
Educational estimate only. The Warsaw (fat-protein unit) method is an advanced insulin-pump technique — individualize timing and dosing with your diabetes care team.
Fat in Meal
g
0150
Protein in Meal
g
0150
Insulin-to-Carb Ratio
g/unit
150
Fat-Protein Units (FPU)
0
Extra Insulin
0 u
Extended Bolus
None
No extension needed
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What is a Warsaw Method?
A Warsaw Method Calculator estimates the additional insulin and extended dosing timing that may be needed for meals high in fat and protein, using the fat-protein unit (FPU) approach widely taught in insulin pump education. Unlike carbohydrate, which raises blood glucose relatively quickly, fat and protein are digested more slowly and can produce a delayed, prolonged glucose rise that standard mealtime dosing alone may not fully cover.
This calculator converts fat and protein grams into fat-protein units — with 100 kcal from combined fat and protein equal to 1 FPU — then estimates the extra insulin needed and a suggested extended bolus duration. It's meant to be used alongside standard carbohydrate-based dosing from the Insulin Dosage Calculator, not as a replacement for it.
How to use this Warsaw Method calculator
- Estimate the Fat in Meal, in grams, for the meal you're evaluating.
- Estimate the Protein in Meal, in grams, for the same meal.
- Enter your prescribed Insulin-to-Carb Ratio (grams of carbohydrate covered per unit of insulin).
- Review the Fat-Protein Units (FPU) result, shown as the primary output.
- Check the Extra Insulin and Suggested Extended Bolus Duration results, and discuss how to apply fat-protein counting to your actual insulin regimen with your diabetes care team.
Formula & Methodology
Fat-Protein Units (FPU) = [(Fat grams × 9) + (Protein grams × 4)] ÷ 100 Carb-Equivalent Grams = FPU × 10 Extra Insulin = Carb-Equivalent Grams ÷ Insulin-to-Carb Ratio This follows the Warsaw method / fat-protein unit approach used in insulin pump education (based on the Bruttomesso et al. extended-bolus dosing pattern), where 1 FPU equals 100 kcal from fat and protein and is dosed like 10 g of carbohydrate, delivered as an extended bolus. Suggested duration follows a commonly taught rule of roughly 1 additional hour of extension per FPU, capped at 8 hours. Worked example: a meal with 20 g fat and 30 g protein, insulin-to-carb ratio 1:10: - Fat-protein energy = (20 × 9) + (30 × 4) = 180 + 120 = 300 kcal - FPU = 300 ÷ 100 = 3 FPU - Carb-equivalent = 3 × 10 = 30 g - Extra insulin = 30 ÷ 10 = 3 units, suggested extended bolus over roughly 5 hours
Frequently Asked Questions
The Warsaw method, also called the fat-protein unit (FPU) method, is an approach used in insulin pump therapy to dose additional insulin for meals high in fat and protein, which raise blood glucose more slowly and for longer than carbohydrate alone. It converts fat and protein calories into fat-protein units, dosed similarly to carbohydrate but delivered as an extended bolus over time.
One FPU represents 100 kilocalories from combined fat and protein, calculated as (fat grams × 9) plus (protein grams × 4), divided by 100. For example, a meal with 20 g of fat and 30 g of protein provides 300 kcal from fat and protein, or 3 FPU.
Carbohydrate raises blood glucose relatively quickly, which standard mealtime insulin is timed to match, but fat and protein are digested more slowly and can raise glucose gradually over several hours after a meal. Without additional coverage, this delayed rise can cause post-meal glucose to climb even when the initial carb-based dose was accurate.
This calculator uses a commonly taught rule of thumb where each fat-protein unit adds roughly one hour to the suggested extended bolus duration, starting around 3 hours for 1 FPU and capping at about 8 hours for larger fat-protein loads. Actual timing should always be individualized with your diabetes care team based on your own glucose response patterns.
The Warsaw method adds to, rather than replaces, standard carbohydrate-based dosing — you would typically calculate your regular meal and correction dose using the [Insulin Dosage Calculator](/insulin-dosage-calculator/), then add the extra insulin and extended timing suggested by the Warsaw method for high-fat, high-protein components of the meal.
An extended (or square-wave) bolus delivers insulin gradually over a set period rather than all at once, while a combo bolus delivers part of the dose immediately and the rest gradually — both are features available on most insulin pumps. These delivery patterns are designed to better match the slower, prolonged glucose rise from fat and protein.
The extended bolus feature this method relies on is primarily available on insulin pumps, though people using multiple daily injections sometimes apply modified versions of fat-protein counting with split or delayed injections under their care team's guidance. Pump users typically have the most precise ability to implement true extended dosing.
No — it's specifically relevant for meals with substantial fat and protein content relative to carbohydrate, such as pizza, fried foods, or protein-heavy meals with minimal carbs. Meals that are primarily carbohydrate with low fat and protein typically don't need this additional adjustment.
Fat-protein unit dosing guidelines are based on general population patterns and clinical experience rather than a single precise formula, so individual glucose responses to fat and protein vary considerably. Many people refine their personal fat-protein dosing ratios over time in partnership with their diabetes care team using glucose monitoring data.
Extended bolus dosing for fat and protein is an advanced diabetes management technique that carries real risk of hypoglycemia or hyperglycemia if applied incorrectly, so this tool is intended purely as an educational illustration of the method's math. Always work with your endocrinologist or diabetes educator before using fat-protein counting in your actual insulin regimen.
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