This is another application of Dr Richard Bernstein’s Law of Small Numbers.

Imagine one meal requires eight units of rapid-acting insulin while another requires only one or two.

Food digestion and injected insulin absorption are never perfectly predictable. An error involving a large input has the potential to create a larger glucose excursion than an error involving a small one.

This is one reason reducing carbohydrate can actually make glucose more, rather than less, predictable.

Nutritional ketosis adds another interesting dimension. When the body is accustomed to using glucose, fatty acids and ketones, glucose isn’t its only available fuel. This is what I call multifuelling.

That doesn’t make hypoglycaemia harmless, nor does it change the need to treat a hypo appropriately. It changes the metabolic background in which glucose management takes place.

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.

Food is only one influence on insulin.

Physical activity can greatly increase insulin sensitivity, sometimes for many hours. Stress, sleep, temperature, illness and time of day can also change glucose behaviour and insulin requirements.

These are examples of why the Five Foundations of Health — nutrition, activity, mindset, environment and circadian rhythms — matter when thinking about Optimised Insulin.

One particular risk when reducing carbohydrate is continuing to use insulin doses designed for the previous diet. Insulin sensitivity may also change over subsequent weeks and months, so basal insulin needs attention as well as mealtime doses.

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