Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base.

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. 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. It has never shown side effects comparable with 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 randomized 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.

Low carbohydrate diet in type 1 diabetes, long-term improvement and adherence: A clinical audit.

BACKGROUND: Reduction of dietary carbohydrates and corresponding insulin doses stabilizes and lowers mean blood glucose in individuals with type 1 diabetes within days. The long-term adherence for persons who have learned this technique is unknown. To assess adherence over 4 years in such a group the present audit was done retrospectively by record analysis for individuals who have attended an educational course. Adherence was assessed from HbA1c changes and individuals' own reports. FINDINGS: Altogether 48 persons with diabetes duration of 24 ± 12 years and HbA1c > = 6.1% (Mono-S; DCCT = 7.1%) attended the course. Mean HbA1c for all attendees was at start, at 3 months and 4 years 7.6% ± 1.0%, 6.3 ± 0.7%, 6.9 ± 1.0% respectively. The number of non-adherent persons was 25 (52%). HbA1c in this group was at start, at 3 months and 4 years: 7.5 ±1.1%, 6.5 ± 0.8%, 7.4 ± 0.9%. In the group of 23 (48%) adherent persons mean HbA1c was at start, at 3 months and 4 years 7.7 ± 1.0%, 6.4 ± 0.9%, 6.4 ± 0.8%. CONCLUSION: Attending an educational course on dietary carbohydrate reduction and corresponding insulin reduction in type 1 diabetes gave lasting improvement. About half of the individuals adhered to the program after 4 years. The method may be useful in informed and motivated persons with type 1 diabetes. The number needed to treat to have lasting effect in 1 was 2.

Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal.

Current nutritional approaches to metabolic syndrome and type 2 diabetes generally rely on reductions in dietary fat. The success of such approaches has been limited and therapy more generally relies on pharmacology. The argument is made that a re-evaluation of the role of carbohydrate restriction, the historical and intuitive approach to the problem, may provide an alternative and possibly superior dietary strategy. The rationale is that carbohydrate restriction improves glycemic control and reduces insulin fluctuations which are primary targets. Experiments are summarized showing that carbohydrate-restricted diets are at least as effective for weight loss as low-fat diets and that substitution of fat for carbohydrate is generally beneficial for risk of cardiovascular disease. These beneficial effects of carbohydrate restriction do not require weight loss. Finally, the point is reiterated that carbohydrate restriction improves all of the features of metabolic syndrome.

Low-carbohydrate diet in type 2 diabetes. Stable improvement of bodyweight and glycemic control during 22 months follow-up.

BACKGROUND: Low-carbohydrate diets in the management of obese patients with type 2 diabetes seem intuitively attractive due to their potent antihyperglycemic effect. We previously reported that a 20% carbohydrate diet was significantly superior to a 55-60% carbohydrate diet with regard to bodyweight and glycemic control in 2 non-randomised groups of obese diabetes patients observed closely over 6 months. The effect beyond 6 months of reduced carbohydrate has not been previously reported. The objective of the present study, therefore, was to determine to what degree the changes among the 16 patients in the low-carbohydrate diet group at 6-months were preserved or changed 22 months after start, even without close follow-up. In addition, we report that, after the 6 month observation period, two thirds of the patients in the high-carbohydrate changed their diet. This group also showed improvement in bodyweight and glycemic control. METHOD: Retrospective follow-up of previously studied subjects on a low carbohydrate diet. RESULTS: The mean bodyweight at the start of the initial study was 100.6 +/- 14.7 kg. At six months it was 89.2 +/- 14.3 kg. From 6 to 22 months, mean bodyweight had increased by 2.7 +/- 4.2 kg to an average of 92.0 +/- 14.0 kg. Seven of the 16 patients (44%) retained the same bodyweight from 6 to 22 months or reduced it further; all but one had lower weight at 22 months than at the beginning. Initial mean HbA1c was 8.0 +/- 1.5%. After 6 and 12 months it was 6.6 +/- 1.0 % and 7.0 +/- 1.3%, respectively. At 22 months, it was still 6.9 +/- 1.1%. CONCLUSION: Advice on a 20% carbohydrate diet with some caloric restriction to obese patients with type 2 diabetes has lasting effect on bodyweight and glycemic control.

A low-carbohydrate diet may prevent end-stage renal failure in type 2 diabetes. A case report.

An obese patient with type 2 diabetes whose diet was changed from the recommended high-carbohydrate, low-fat type to a low-carbohydrate diet showed a significant reduction in bodyweight, improved glycemic control and a reversal of a six year long decline of renal function. The reversal of the renal function was likely caused by both improved glycemic control and elimination of the patient's obesity. Insulin treatment in type 2 diabetes patients usually leads to weight increase which may cause further injury to the kidney. Although other unknown metabolic mechanisms cannot be excluded, it is likely that the obesity caused by the combination of high-carbohydrate diet and insulin in this case contributed to the patient's deteriorating kidney function. In such patients, where control of bodyweight and hyperglycemia is vital, a trial with a low-carbohydrate diet may be appropriate to avoid the risk of adding obesity-associated renal failure to already failing kidneys.

Lasting improvement of hyperglycaemia and bodyweight: low-carbohydrate diet in type 2 diabetes. A brief report.

In two groups of obese patients with type 2 diabetes the effects of 2 different diet compositions were tested with regard to glycaemic control and bodyweight. A group of 16 obese patients with type 2 diabetes was advised on a low-carbohydrate diet, 1800 kcal for men and 1600 kcal for women, distributed as 20% carbohydrates, 30% protein and 50% fat. Fifteen obese diabetes patients on a high-carbohydrate diet were control group. Their diet, 1600-1800 kcal for men and 1400-1600 kcal for women, consisted of approximately 60% carbohydrates, 15% protein and 25% fat. Positive effects on the glucose levels were seen very soon. After 6 months a marked reduction in bodyweight of patients in the low-carbohydrate diet group was observed, and this remained one year later. After 6 months the mean changes in the low-carbohydrate group and the control group respectively were (+/-SD): fasting blood glucose (f-BG): -3.4 +/- 2.9 and -0.6 +/- 2.9 mmol/l; HBA1c: -1.4 +/- 1.1% and -0.6 +/- 1.4%; Body Weight: -11.4 +/- 4 kg and -1.8 +/- 3.8 kg; BMI: -4.1 +/- 1.3 kg/m_ and -0.7 +/- 1.3 kg/m_. Large changes in blood glucose levels were seen immediately. A low-carbohydrate diet is an effective tool in the treatment of obese patients with type 2 diabetes.

Lasting improvement of hyperglycaemia and bodyweight: low-carbohydrate diet in type 2 diabetes--a brief report.

UNLABELLED: In two groups of obese patients with type 2 diabetes the effects of 2 different diet compositions were tested with regard to glycaemic control and bodyweight. A group of 16 obese patients with type 2 diabetes was advised on a low-carbohydrate diet, 1800 kcal for men and 1600 kcal for women, distributed as 20 % carbohydrates, 30 % protein and 50 % fat. Fifteen obese diabetes patients on a high-carbohydrate diet were control group. Their diet, 1600-1800 kcal for men and 1400-1600 kcal for women, consisted of approximately 60 % carbohydrates, 15 % protein and 25 % fat. Positive effects on the glucose levels were seen very soon. After 6 months a marked reduction in bodyweight of patients in the low-carbohydrate diet group was observed, and this remained one year later. After 6 months the mean changes in the low-carbohydrate group and the control group respectively were (+/-SD): fasting blood glucose (f-BG): -3.4+/-2.9 and -0.6+/-2.9 mmol/l; HBA1c: -1.4+/-1.1 % and -0.6+/-1.4 %; Body Weight: -11.4+/-4 kg and -1.8+/-3.8 kg; BMI: -4.1+/-1.3 kg/m_ and -0.7+/-1.3 kg/m_. Large changes in blood glucose levels were seen immediately. CONCLUSION: A low-carbohydrate diet is an effective tool in the treatment of obese patients with type 2 diabetes.

A low carbohydrate diet in type 1 diabetes: clinical experience--a brief report.

Due to failure to achieve control twenty-two patients with type 1 diabetes with symptomatic fluctuating blood glucose started on a diet limited to 70-90 g carbohydrates per day and were taught to match the insulin doses accordingly. The caloric requirements were covered by an increased intake of protein and fat. The purpose was to reduce the blood glucose fluctuations, the rate of hypoglycaemia and to improve HbA1c. After three and 12 months the rate of hypoglycaemia was significantly lowered from 2.9 +/- 2.0 to 0.2 +/- 0.3 and 0.5 +/- 0.5 episodes per week respectively. The HbAlc level was significantly lowered from 7.5 +/- 0.9% to 6.4 +/- 0.7% after three months and was still after 12 months 6.4 +/- 0.8%. The meal insulin requirements were reduced from 21.1 +/- 6.7 I.U./day to 12.7 +/- 3.5 I.U./day and 12.4 +/- 2.6 I.U./day after three and 12 months respectively. Furthermore the triglyceride level was significantly lowered whereas the levels for total cholesterol and HDL-cholesterol were unchanged. The present report shows that a 70-90 g carbohydrate diet is a feasible long-term alternative in the treatment of type 1 diabetes and leads to improved glycaemic control.