MEAL BOLT: A Tutorial for Insulin Dosing
M — Measure the Meal
Consider the total composition of your plate. While carbohydrate counting is the standard, many find that accounting for fat and protein is equally important. High fat and protein content can often delay the digestion of carbohydrates, which may impact when insulin is needed.
E — Evaluate the Variables
Before deciding on a dose, it can be helpful to evaluate your current "starting line." This includes checking your current blood glucose, noting any Insulin on Board (IOB) from previous doses, and considering recent or upcoming physical activity, which can significantly alter insulin sensitivity.
A — Add the Carbohydrate Base
Start with the "base" dose required for the carbohydrates you are about to consume. This is typically determined by your insulin-to-carb ratio (ICR) as prescribed by your doctor.
L — Layer a Correction
If your blood glucose is above your target range, you might consider layering a correction dose. For example, some people use a formula such as: (Current BG - Target BG) / Correction Factor = Units to Add. From this total, many people subtract their remaining IOB to avoid "stacking" insulin and causing a low later.
B — Build the Shape
Not all meals require the insulin at once. "Building the shape" refers to how the dose is delivered. Those using a pump might consider an "extended" or "dual-wave" bolus for high-fat meals. Those on MDI (injections) might discuss with their doctor if splitting a dose into two separate injections is appropriate for certain food types.
O — Offset the Timing (Pre-Bolus)
Timing is often as important as the dose itself. "Offsetting" is the practice of matching the insulin’s peak action with the meal’s glucose peak. This is commonly known as a "pre-bolus." Factors like the type of food and your current blood glucose level typically dictate how many minutes the insulin is given before the first bite.
L — Look at the Curve
The process doesn't end when the meal is over. By observing the post-meal trend on a CGM or via finger sticks, you can see how well the dose and timing matched the meal. This data is the key to mastering future management.
T — Tweak for Next Time
Diabetes is a game of patterns. If the "Look" phase showed a spike or a drop, use that information to tweak the variables for the next time you eat a similar meal. Small, incremental adjustments are often the safest way to find what works for your unique needs.
Summary
M – Measure the Meal: Consider the impact of carbs, fat, protein, and glycemic index.
E – Evaluate the Variables: Review current BG, active IOB, activity levels, and stress.
A – Account for Base Units: Consider the dose for carbohydrates based on your doctor-prescribed ratio.
L – Layer a Correction: Identify if a correction is needed (e.g., Current BG minus Target, divided by Correction Factor, minus IOB).
B – Build the Bolus Shape: Discuss with your team if an upfront vs. extended delivery (or split dose) is appropriate.
O – Offset the Timing: Determine the optimal lead time (pre-bolus) to match insulin action to the meal.
L – Look at the Curve: Observe CGM trends at intervals (e.g., 1h, 3h, 5h) to see how the strategy performed.
T – Tweak for Next Time: Use your observations to refine and adjust variables for future similar meals.
Because insulin is a powerful medication, please review these safety points:
Confirm with Your Team: Have you discussed your Insulin-to-Carb Ratio (ICR) and Correction Factor (CF) with your doctor? Never use numbers or ratios that haven't been medically vetted for you.
Account for IOB: Are you "stacking"? Always check your Insulin on Board. Adding a full correction to a previous dose that is still active is a leading cause of severe hypoglycemia.
Check Your Activity: Are you about to exercise or have you recently finished a workout? Physical activity can significantly increase insulin sensitivity and may require a reduction in your estimated dose.
The "Pre-Bolus" Caution: When offsetting (pre-bolusing), ensure you have the meal in front of you and are ready to eat. If your blood glucose is already low or dropping rapidly, a pre-bolus may be dangerous.
Verify Your Math: Always double-check your manual calculations. A simple decimal point error can lead to a 10x dosing mistake.
Monitor the Trend: After a "Tweak" or a new bolus strategy, stay vigilant. Keep your CGM alerts active or perform manual finger sticks to ensure you are trending safely.
Have a Rescue Plan: Always have fast-acting glucose (tabs, juice, etc.) and a glucagon emergency kit nearby in case your estimate is higher than your body requires.