Dietary Carbohydrate restriction as the first approach in diabetes management. Critical review and evidence base

Abstract

The inability of current recommendations to control the epidemic of diabetes, the specific failure of the prevailing low-fat diets to improve obesity, cardiovascular risk or general health and the persistent reports of some serious side effects of commonly prescribed diabetic medications, in combination with the continued success of low-carbohydrate diets in the treatment of diabetes and metabolic syndrome without significant side effects, point to the need for a reappraisal of dietary guidelines.

Graphical Abstract
Highlights

•We present major evidence for low-carbohydrate diets as first approach for diabetes.

•Such diets reliably reduce high blood glucose, the most salient feature of diabetes.

•Benefits do not require weight loss although nothing is better for weight reduction.

•Carbohydrate-restricted diets reduce or eliminate medication.

•There are no side effects comparable to those seen in intensive treatment with drugs.

The benefits of carbohydrate restriction in diabetes are immediate and well-documented. Concerns about the efficacy and safety are long-term and conjectural rather than data-driven. Dietary carbohydrate restriction reliably reduces high blood glucose, does not require weight loss (although is still best for weight loss) and leads to the reduction or elimination of medication and has never shown side effects comparable to those seen in many drugs.

Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They represent the best-documented, least controversial results. The insistence on long-term random-controlled trials as the only kind of data that will be accepted is without precedent in science. The seriousness of diabetes requires that we evaluate all of the evidence that is available. The 12 points are sufficiently compelling that we feel that the burden of proof rests with those who are opposed.

“At the end of our clinic day, we go home thinking, ‘The clinical improvements are so large and obvious, why don't other doctors understand?’ Carbohydrate restriction is easily grasped by patients: because carbohydrates in the diet raise the blood glucose, and as diabetes is defined by high blood glucose, it makes sense to lower the carbohydrate in the diet. By reducing the carbohydrate in the diet, we have been able to taper patients off as much as 150 units of insulin per day in eight days, with marked improvement in glycemic control – even normalization of glycemic parameters.”

— Eric Westman, MD, MHS [1].

Reduction in dietary carbohydrate as a therapy for diabetes has a checkered history. Before and, to a large extent, after the discovery of insulin, it was the preferred therapeutic approach [2]. Only total reduction in energy intake was comparable as an effective dietary intervention. The rationale was that both type 1 and type 2 diabetes represent disruptions in carbohydrate metabolism. The most salient feature of both diseases is hyperglycemia and the intuitive idea that reducing carbohydrate would ameliorate this symptom is borne out by experiment with no significant exceptions. Two factors probably contributed to changes in the standard approach. The ascendancy of the low-fat paradigm meant that the fat that would replace the carbohydrate that was removed was now perceived as a greater threat, admittedly long-term, than the immediate benefit from improvement in glycemia. The discovery of insulin may have also cast diabetes — at least type 1 — as a hormone deficiency disease where insulin (or more recent drugs) were assumed to be a given and dietary considerations were secondary. For these and other reasons, dietary carbohydrate holds an ambiguous position as a therapy.

Although low-carbohydrate diets are still controversial, they have continued to demonstrate effectiveness with little risk and good compliance. At the same time, the general failure of the low-fat paradigm to meet expectations, coupled with continuing reports of side effects of different drugs indicates a need for re-evaluation of the role for reduction in carbohydrate. The current issue seems to be whether we must wait for a long-term random controlled trial (RCT) or whether we should evaluate all the relevant information. Practical considerations make it virtually impossible to fund a large study of non-traditional approaches. In any case, the idea that there is one kind of evidence to evaluate every scientific question is unknown in any science. Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They are proposed as the most well-established, least controversial results. It is not known who decides what constitutes evidence-based medicine but we feel that these points are sufficiently strong that the burden of proof rests on critics. The points are, in any case, intended to serve as the basis for improved communication on this topic between researchers in the field, the medical community, and the organizations creating dietary guidelines. The severity of the diabetes epidemic warrants careful and renewed consideration of our assumptions about the diet for diabetes.

Definitions: A lack of agreed-upon definitions for “low-carbohydrate diet” has been a persistent barrier to communication. We propose the definitions in Table 1 to eliminate ambiguity. Each definition is based on use in multiple publications by those authors who have performed the experimental studies 3, 4, 5, 6.

Full text here: http://www.nutritionjrnl.com/t

DCUK featured this in their news section as per usual no link to the article was given, this prompted a comment from David Mendosa:

Nicolai Worm Thank you, Dr. Worm. Thanks both for providing the link and to being one of the authors of this important review. Without your link I don't think that I could have found the study. It seems to me almost that diabetes.co.uk wanted to hide it. I have never come across a review of a study that didn't give a single name of an author or the title of the study.

Graham