New Zealand researcher defends use of low-carb advice for type 2 diabetes

A researcher from Auckland’s University of Technology, in New Zealand, has taken a stand against claims that low-carb diets aren’t evidence-based medicine and shouldn’t be recommended to people with type 2 diabetes.
A low-carb enthusiast himself, George Henderson has fervently responded to these statements made in an opinion editorial written by a Glaswegian GP called Margaret McCartney.
The controversial op-ed, which appeared in the British Medical Journal, discusses what a low-carb diet can and can’t do for type 2 diabetes and argues that it is premature to advocate prescribing it to patients based on available evidence.
McCartney is especially critical of how nutrition research is translated in media headlines, which most often position low-carb diets as “miracle fixes.”
She also questions whether the growing body of mostly observational and anecdotal evidence in favour of cutting down on carb intake is enough to justify integrating this advice into guidelines and medical practice.
In his rebuttal, Henderson explains that by claiming that the evidence for low-carb diets is insufficient, we risk “supporting a system for which there is even less evidence, and a less excusable absence of evidence.”
In fact, a review he authored with colleagues in the New Zealand Medical Journal found no evidence that higher-carb diets for type 2 diabetes were tested against anything other than slightly less high carb diets before they were introduced.
Henderson also points out that, albeit brief, McCartney’s analysis surprisingly only quotes studies which reported negative or neutral metabolic and weight loss outcomes with a low-carb diet.
Some well-designed trials left out by McCartney and put forward by Henderson include those indicating at what level of carb restriction benefits start to appear or explaining how lower carb diets work to improve glucose control.
Henderson is also of the opinion that part of the reason why low-carb diets have shown weaker effects in some of the longer term studies she mentions is because of low adherence driven by a lack of support rather than declining efficacy.
While McCartney advocates change within the bounds of the status quo, Henderson concludes by saying that it would be unacceptable and unfair not to offer advice on using a low-carb diet to patients with type 2 diabetes more systematically where warranted.