@MarkR
You may find this
article by Katie Caldesi interesting. She is the co-author of
this book, Reverse your Diabetes [type 2] Cookbook; after clicking on link click on Read Sample below the front cover image. This has a foreword by Dr David Unwin and an article by Jenny Phillips, a nutritionist, which goes into low carb in some detail.
It proposes this low carb scale:
Keto Strict Moderate Liberal
Under 30g Up to 50g Up to 70g Up to 130g
Keto: This is for people wanting to lose weight quickly and are prepared to be strictly limited in what they can eat to achieve their goals.
Strict low-carb: limiting dietary carbohydrate to under 50g (2oz) per day affords tight glycaemic control and is a reasonable therapeutic aim for type 2 diabetics and those suffering with low energy or cravings.
Moderate low-carb: 75–100g (2¾–3½oz) carbs per day. This enables a wide and varied diet and is a good starting point into carbohydrate restriction. It is also a good target for the long-term as it is not too restrictive.
Liberal low-carb: up to 130g (4½oz) carbs per day. Suitable for those who are lean and healthy, with an active lifestyle. If you have high activity levels and are lean, fit and healthy, then you may wish to retain some higher starch foods within your diet. However, to achieve health benefits, your overall diet should contain sufficient high-quality food, including protein, healthy fat and mostly unprocessed, slow-release carbohydrates, such as oats and starchy vegetables, like sweet potatoes, beetroot and pulses. Even for athletes, the days of heavy carb-loading are waning – England Rugby, for example, encourages its players to consume lots of vegetables and protein in addition to slow-release carbohydrates.