Getting the right mealtime insulin dose can get messy fast. I know, because I spent years disappearing down rabbit holes trying to make sense of it. At one point I even built a 156-page interactive MSc module — full bells, whistles, and unnecessary complexity — while stuck in those warrens. If you’re curious, you can see the story here.
Dani, let’s focus on what to do, not my scientific detours.
I’ve made a guide that shows you exactly where to start.
This guide will teach you how to adjust insulin doses and lifestyle to maximise time in range (4.0–10.0mmol/L or 70–180mg/dL) when eating:
High-carb meals
Balanced meals
High-fat meals
This section will not cover dosing for low-carb or ketogenic meals.
I’ve already explained here why Grace and Jude won’t need that if they follow Dynamic Glucose Management.
As an adult, though, you might want to experiment. If so, you can see how I approached it in the 120-day carb experiment, or go full nerd mode with the 156-page guide.
Before we split into the three meal types, let’s remind ourselves why glucose spikes after eating — even when insulin is given well ahead of time.
Exactly: the lack of insulin in the portal vein is the nemesis for people with type 1 diabetes.
Now, what about high-fat meals?
Why does glucose often start climbing three hours after a fatty meal and demand a bucket load of insulin?
Brilliant question. This podcast nails the mechanism: Episode 7: Fundamentals of The Glucose Never Lies.
This is also where one of my mentors, Peter Attia, comes in.
I didn’t understand the DAG effect until late 2020 — after I’d already written the 156-page guide — so it’s not in there yet.
Peter interviewed the researcher who uncovered a key driver of insulin resistance.
The Drive: Episode 140 — Gerald Shulman’s deep dive into insulin resistance.
That episode helped me crystallise what’s going on:
The DAG (diacylglycerol) effect
More importantly, it explained why pizza, fish and chips, and takeaways can send glucose north three hours later — and why so much extra insulin suddenly seems “necessary”.
It also showed me something else: activity and exercise can burn through that insulin-resistant state. That’s what I accidentally did on Christmas Day 2019, before I even knew DAGs were the enemy.
Those 6000 high knees late in the evening blunted the DAG effect without needing to crank insulin to the sky.
A tool for high-fat meals that doesn’t rely on astronomical circulating insulin? Yes please.
So what is the DAG effect?
Time for a diagram.
Key takeaways:
- High-fat meals slow digestion.
- Insulin resistance often kicks in about three hours after a high-fat meal.
- High fat levels in liver and muscle cells promote the creation of DAGs (diacylglycerols) as fats are metabolised.
- DAGs interfere with insulin signalling, so insulin can’t “unlock” muscle and liver cells properly.
- Glucose then stays high unless you add a lot more insulin or burn up DAGs for energy via activity/exercise.
Right. Enough theory. Let’s get into what to do in practice.
Next step: High Carbohydrate Meals
