Type 2 Diabetes: Should You Recommend a Low-Carb Diet?

Dawn O'Shea

March 09, 2020

A low-carbohydrate diet does not improve weight but may help in the management of blood glucose, according to a new draft report from Public Health England (PHE).

PHE’s Scientific Advisory Committee on Nutrition (SACN) has published draft findings on the effect of low- vs high-carbohydrate diets for people with type 2 diabetes.

However, one GP who champions low-carb diets for type 2 diabetes told Medscape UK the bar seems to have been set high for this dietary approach.

Expert Assessment

The comprehensive review was conducted by a joint working group comprising members of SACN and members nominated by Diabetes UK, NHS England, the British Dietetic Association, the Royal College of Physicians and the Royal College of General Practitioners.

The effects of lower compared with higher carbohydrate diets were considered on a range of outcomes including body weight and measures of blood glucose concentrations.

Following a robust, systematic assessment of the available evidence, the draft conclusions are:

  • For body weight, there is no difference between lower and higher carbohydrate diets in the long term (≥12 months). Short-term weight change was not considered.

  • For blood glucose (sugar) levels, lower carbohydrate diets may have benefits over higher carbohydrate diets in the short term, but the longer-term effects are unclear.

Current UK government advice is that for the general population, around 50% of total dietary energy should be from starchy carbohydrates (such as potatoes, bread and rice), opting for higher fibre or wholegrain versions where possible. People with type 2 diabetes are currently advised to follow healthy eating advice for the general population.

'Low-Carb GP' Responds

Dr David Unwin is a GP who has reported success with diabetes patients on low-carb diets. He's also the Royal College of GPs' (RCGP) National Champion for Collaborative Care and Support Planning in Obesity & Diabetes and RCGP clinical expert in diabetes.

Responding to the report by email he told us: "It seems to me that they are placing the bar higher for low-carb than for other approaches. I am not aware of interventional (non-epidemiological) evidence for any other approach in the longer term?

"For example, where is the robust evidence that a low-fat diet is an effective treatment for type 2 diabetes in the longer term?

"Low-carb was standard treatment for type 2 diabetes for about 100 years. It is not a new thing, being used effectively by Dr Rollo for the first time in 1797.

"At the Norwood surgery we have offered a low-carb option to our T2D patients for 7 years. To date 141 patients have opted to cut sugar and starchy carbs resulting in an average improvement in HbA1c of 21 mmol/mol, so that 70 patients have achieved drug-free T2D remission so far. In addition we have reduced the number of prescriptions for diabetes at a practice level, spending £50,000 less on these drugs per year than is average for our area.

"The bias where low carb has to produce better evidence than any other approach makes it harder for clinicians like me to do our job."

PHE is inviting comments on the draft report. The consultation closes on 8th April 2020.

Adapted from Univadis from Medscape with additional reporting by Tim Locke.


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