Lack of clear evidence for low carb diets in type 2 diabetes

Picture of red meat

This systematic review set out to establish whether low-carbohydrate diets, which are known to be effective for short-term weight loss in non-diabetic obese people, work in people with type 2 diabetes.

Clinical question:

In type 2 diabetes, do low-carbohydrate diets, as compared to alternative dietary advice, lead to improved glycaemic control or increased weight loss?

The comparisons included Low Fat Diet (LFD), Usual Care Diet (UCD) or Low Glycemic Index Diet (LGID).

The evidence

It is not clear how many individual randomised trials were found. However, the reveiwers note that most of the studies, including the longer term ones, did not find a significant benefit for low-carb diets in terms of weight loss.

They did find one longer term study that found a benefit for a mediterranean-style diet in reducing HbA1c, however.

Appraisal hints:

Users of this research should consider:

  • Whether the reviewers could have missed important research (e.g. they did not search EMBASE).
  • Were the intervention similar enough?  Were the comparisons realistic?
  • How other treatments would affect outcomes.
  • It may be better to look for a better quality individual study that closely matches the population and interventions that are relevant and achievable in your setting.


Castañeda-González LM, Bacardí Gascón M, Jiménez Cruz A. Effects of low carbohydrate diets on weight and glycemic control among type 2 diabetes individuals: a systemic review of RCT greater than 12 weeks. Nutr Hosp. 2011 Dec;26(6):1270-6.

Share this post: Share on Facebook Tweet this on Twitter Share on LinkedIn Share on Google+ Share via email


I am an information scientist with an interest in making knowledge from systematic research more accessible to people who need it. This means you. I've been attempting this in the area of Evidence-Based Health Care since 1995. So far the results have been mixed. For some reason we expected busy clinicians to search databases and appraise papers instead of seeing patients. We also expected publishers to make the research freely available to the people who paid for it.. Ha! Hence The National Elf service.

More posts - Website

Follow me here –