A serious rethink on carbs taught to me by Mastering Diabetes

I've observed the pattern so many thousands of times: eating high carb foods cause the biggest fluctuations in my post-meal glucose. Therefore, high carbs are problematic and best avoided. This is the deeply ingrained mental model I've been working with for the last 25 years to manage my type 1 diabetes. How could this be wrong?

Well, owing to some extra free time over lockdown, I came across the Mastering Diabetes book.

I've had so many aha moments reading this and relating the evidenced based approaches with my own experience with T1D. One of the many things I took away was a complete rethink on carbs.


It's refreshing to see an approach that goes against the grain of conventional diabetes wisdom and advocates carbs as the main dietary component. This appeals to me particularly because I do a lot of endurance sport. Carbohydrates are necessary for keeping glycogen stores topped up which are called upon to fuel intense workouts. I've followed a number of low carb approaches in the past and, whilst they gave me great glucose control, they often left me a little flat on the sharp end of hard workouts.

The book states that labelling carbs as the enemy has actually given rise to a whole host of the confusion that we see today around carbs and diabetes. The carbs story, as detailed in the book, is much more nuanced for two main reasons.

Firstly, in order to talk meaningfully about carbs it's important to distinguish between refined and unrefined. Refined carbs are essentially those that have undergone processing of one kind or another for example removing the bran from a grain and grinding the grain to make flour. These types of carbs tend to get absorbed very quickly by the body. The opposite is true of unrefined carbs which are composed of longer chain carbohydrate molecules and release glucose into the bloodstream much more slowly. Plant foods, the main component of the mastering diabetes approach, are a fantastic source of unrefined carbs.

The second reason is that high glucose values following a high carb meal are actually indicative of a state of insulin resistance and not an issue with carbs themselves. Insulin resistance is a state whereby the body's tissues have a lower level of response to insulin meaning glucose cannot be absorbed as efficiently by cells leaving it lingering in the blood.

Up to this point I've sort of thought that insulin resistance was more of a type 2 diabetes problem but, as the book clarified, it can and does occur in all types of diabetes. In fact the mechanisms that bring about insulin resistance are the same regardless of types of diabetes. Insulin resistance is caused by:

The accumulation of fat in tissues that are not designed to store large quantities of fat

For type 1's like myself, becoming more sensitive to insulin has the advantage that I need to take less of the stuff. Less insulin means a smaller margin for error day-to-day and therefore I have a greater chance of keeping my glucose levels steady.

Whilst avoiding post meal spikes and generally taking less insulin are good enough reasons for me to work on become as sensitive as possible to insulin, the other perhaps more important reason is because insulin resistance is the cause of whole host of diabetes complications - basically you name it, it's there.

The Mastering Diabetes approach consists of a 5-pillar approach to maximising insulin sensitivity. I won't go into all 5 elements in this post but the first is adopting a low-fat plant based diet which, if the references are to go by, seems to be the biggest bang for your buck when trying to reverse insulin resistance. I first started following the diet during the summer and could not quite believe how much more effective my insulin became!

Another huge eye opener for me in the book was the idea that tight glucose control alone is not sufficient alone to minimise risk of future complications. Research such as this paper, referenced in the book, concluded in a study of 603 type 1 patients that insulin resistance was a better predictor of future coronary artery disease than glucose control!

I've spent the best part of 25 years fixating on HBA1Cs as my overarching success metric when it comes to my diabetes. Whilst long term glucose control is and always will be super important, the book helped me open my perspectives and not over fixate on a single dimension of health.

I really love the evidenced based approach Cyrus and Robby have taken with this book. I've just enrolled in their online coaching course so expect more posts on this topic soon. In the meantime, I'd encourage anyone with diabetes to read this, it taught me so many things and perhaps more importantly caused me to challenge a few of my ingrained assumptions, not least around carbs.