Glucose is an important fuel, and some cells depend upon it. However, the body stores glucose as glycogen and can also make glucose when required through gluconeogenesis. When carbohydrate availability falls, it can increasingly use fatty acids and ketones for energy.

The Type1Keto approach deliberately restricts carbohydrate sufficiently to encourage nutritional ketosis. This isn’t about depriving the body of fuel. It is about increasing access to different fuels.

Rather than relying predominantly on dietary carbohydrate, the body can use glucose, fatty acids and ketones according to circumstances. I call this multifuelling.

For someone with type 1 diabetes, reducing carbohydrate has another important consequence: less carbohydrate generally means less mealtime insulin.

This brings us to Dr Richard Bernstein’s Law of Small Numbers.

Neither food absorption nor injected insulin is perfectly predictable. A meal requiring eight units of insulin leaves considerably more room for a large dosing error than one requiring one or two units. Smaller glucose and insulin inputs tend to produce smaller potential errors.

Nutritional ketosis does not mean stopping insulin.

People with type 1 diabetes require insulin regardless of how little carbohydrate they eat. Insulin requirements can change substantially when carbohydrate is reduced, so insulin needs to be adjusted appropriately.

The objective isn’t minimum insulin. It is Optimised Insulin: as much insulin as needed, as little as possible.

My preference is a varied, nutrient-dense ketogenic diet because nutritional ketosis supports multifuelling while reducing the glucose and insulin inputs I have to manage.

But nutrition isn’t the only influence on insulin. Activity, mindset, environment and circadian rhythms can all alter insulin sensitivity and requirements. Together with nutrition, these form what I call the Five Foundations of Health.

That wider idea of Optimised Insulin is explored in more detail in Shifting Gears.