Type 1 diabetes is often presented through a simple model:

Carbohydrate raises glucose. Insulin lowers it.

That’s true, but incomplete.

Insulin is a major metabolic hormone. It influences glucose uptake and storage, fat storage and release, protein metabolism and which fuels are available to the body.

The question therefore becomes broader than:

“How much insulin do I need for this carbohydrate?”

It becomes:

“How much insulin does my body actually need right now?”

Reducing carbohydrate can reduce mealtime insulin requirements. Maintaining nutritional ketosis can increase access to fatty acids and ketones alongside glucose — multifuelling — while smaller carbohydrate and insulin inputs bring the advantage of the Law of Small Numbers.

But diet is only part of the answer.

This is why I think about insulin through the Five Foundations of Health.

Nutrition determines the incoming fuels and strongly influences mealtime insulin.

Activity uses fuel and can substantially alter insulin sensitivity.

Mindset matters because type 1 diabetes demands continual decisions and adaptation, while stress itself can influence glucose.

Environment, including temperature and light, can affect hormones, glucose and insulin requirements.

Circadian rhythms mean metabolism changes throughout the 24-hour day. Sleep and timing matter as well as food.

These influences don’t operate independently. They continually interact. That leads to what I think is one of the most important lessons in type 1 diabetes:

A ketogenic approach provides a useful nutritional foundation. Nutritional ketosis supports multifuelling. Lower carbohydrate can reduce mealtime insulin requirements and apply the Law of Small Numbers.

But the larger goal is Optimised Insulin across all Five Foundations of Health.

That relationship between nutrition, multifuelling and the wider influences on insulin is explored in more detail in Shifting Gears.