Dr Peter Brukner OAM

Show me the evidence: A low carb approach to managing type 2 diabetes

3 mins read

People invest significant time and money in efforts to improve their health, so examining the scientific evidence behind nutritional advice is important because it helps us seperate the hype from the truth. 

If you’re worried about the evidence behind a low carb approach, rest assured that substantial evidence supports this dietary strategy for managing type 2 diabetes.

There are various evidence levels in medicine and the highest levels are associated with meta-analyses and randomised control trials (RCTs) — the gold standard for scientific experiments. So, let’s look at those related to low carb and type 2 diabetes.

To date, 22 RCTs have compared low carb diets of less than 130g carbohydrate per day to low fat diets of less than 35% or total calories with people living with type 2 diabetes. The studies range in length from three months to two years.

Of these 22 RCTs, 20 of them showed greater improvements in HbA1c for those following a low carbohydrate diet versus those following a low-fat diet. 15 had a clinically significant change in HbA1c compared to the low fat group. 

HbA1c results from published randomised control trials (RCTs) between low carb and low fat diets with type 2 diabetes participants.

Subsequently, 10 meta-analyses have been conducted, which are statistical analyses combining the results of the RCTs. All 10 studies that showed a statistically significant difference favoured the low carb approach. The average improvement in HbA1c levels in the low carb cohort was 9.2mmol/mol) compared to 3.5mmol/mol in the low fat.

In an RCT published in October 2020, Chen et al explored the effect of a moderate (90 g/d) low-carbohydrate diet (LCD) in T2D patients over 18 months. Ninety-two poorly controlled type 2 diabetes patients aged 20–80 years with HbA1c average7.5% (58 mmol/mol) in the previous three months were randomly assigned to a 90 g/d LCD or a traditional diabetic diet. There were statistically significant reductions in HbA1c, blood glucose, medications, weight, waist circumference and blood pressure in the low carb group compared to a traditional diet.

In terms of meta-analysis, in July 2020 Choi et al found similar results - ketogenic diets were better at improving blood sugar control, reducing weight, and improving blood lipids than low-fat diets.

The best level of medical evidence available therefore supports the effectiveness of low carbohydrate and ketogenic diets in the management of type 2 diabetes.

Is there evidence that this type of program can be effectively delivered online?

Online programs similar to Defeat Diabetes have been established for several years in both the UK and the USA.

A recent UK study reviewed results from the Low Carb program on diabetes.co.uk which had over 400,000 participants. Of the 743 participants in the study with a starting HbA1c at or above the type 2 diabetes threshold of 6.5%, 195 (26.2%) reduced their HbA1c to below the threshold while taking no glucose-lowering medications or just metformin.

Of the participants who were taking at least one hypoglycemic medication at baseline, more than 40% reduced one or more of these medications. Almost half of all participants lost at least 5% of their body weight. Overall, glycemic control and weight loss improved, especially for participants who completed all 10 modules of the program. For example, participants with elevated baseline HbA1c who engaged with all 10 weekly modules reduced their HbA1c from 9.2% to 7.1% and lost an average of 6.9% of their body weight.

In the USA, a remote care model run by Virta Health has also proven to be successful, with approximately 50% of participants putting their diabetes into remission.

How does the evidence support the Defeat Diabetes Program?

The Defeat Diabetes program uses the latest scientific evidence in our endeavour to achieve similarly excellent results. We are conducting ongoing research into the effectiveness of our program, the results of which will be published.

Furthermore, the increasing volume of scientific evidence demonstrates the effectiveness of the low carb approach to the management of type 2 diabetes and has been acknowledged by organisations such as Diabetes Australia, the UK National Health Service and the American Diabetes Association.

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