This is an Open Letter to the editor of the Journal of Primary Health Care.
New Zealand’s slow uptake of carbohydrate-reduction in type 2 diabetes management
by Marcus Hawkins GP at the Botany Doctor Medical Practice, and Caryn Zinn from the School of Sport & Recreation, Behavioural Nutrition and Physical Activity, Auckland University of Technology
Submitted: 30 January 2024: Accepted: 8 February 2024
Published: 16 February 2024
© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of The Royal New Zealand College of General Practitioners. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)
Type 2 diabetes (T2DM) is a condition that involves insulin resistance and a reduced ability to control blood glucose. Science and logic indicate that reducing the very nutrient that raises blood sugar, ie carbohydrate, would be worth consideration, yet it’s been overlooked for many years.
Insulin Resistance
Global dietary guidelines have been updated to align with scientific evidence. The American Diabetes Association (ADA), The British Diabetes and Dietetic Associations, Diabetes Canada and Diabetes Australia have included carbohydrate reduction in their official T2DM dietary guidelines. (1, 2)
An ADA 2019 consensus report concluded: ‘reducing overall carbohydrate intake for individuals with diabetes has demonstrated the most evidence for improving glycemia and may be applied in a variety of eating patterns that meet individual needs and preferences’. This report was included in the 2020 ADA Standards of Medical Care in Diabetes update. (3)
Diabetes Australia states: ‘For people with type 2 diabetes, there is reliable evidence that lower carb eating can be safe and useful in lowering average blood glucose levels in the short term (up to 6 months). It can also help reduce body weight and help manage heart disease risk factors such as raised cholesterol and raised blood pressure.’ (4)
New Zealand (NZ) does not endorse carbohydrate reduction as a viable option for individuals, but rather cautions against it. The NZ Society for the Study of Diabetes states in their guidelines ‘meta-analyses show that the benefits of ketogenic diets are unlikely to be sustained’ (5, 6) and the Ministry of Health states ‘Very low carbohydrate diets: Not recommended’. (5)
This is surprising, as clinical trials and primary care practice data report beneficial and sustained results from carbohydrate reduction. (7, 8) Virta Health, a US-based research entity has shown carbohydrate reduction to be safe in prediabetes/T2DM. Their 5-year data concluded their model of care showed excellent retention, sustained clinically significant weight loss, stable glycaemic control and less dependency on diabetes medication. (9)
British general practitioner, Dr David Unwin used carbohydrate reduction to reverse/remit T2DM; of 199 patients with T2DM, 46% achieved drug-free remission, with enormous cost savings from reduced diabetes medication. (10)
In view of the rapid growth of evidence around carbohydrate reduction and T2DM, and the global guideline adoption, we simply ask why NZ is not at least including a carbohydrate reduction approach in its guidelines, alongside other dietary approaches, to manage T2DM.
We now call upon NZ to catch up and follow suit.