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

Authors 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.
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."

Effects of Low-Carbohydrate and Low-Fat Diets

Background: Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations.

Objective: To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors.

Design: A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271)

Setting: A large academic medical center.

Participants: 148 men and women without clinical cardiovascular disease and diabetes.

Intervention: A low-carbohydrate (<40 g/d) or low-fat (<30% of daily energy intake from total fat [<7% saturated fat]) diet. Both groups received dietary counseling at regular intervals throughout the trial.

Measurements: Data on weight, cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months.

Results: Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, −3.5 kg [95% CI, −5.6 to −1.4 kg]; P = 0.002), fat mass (mean difference in change, −1.5% [CI, −2.6% to −0.4%]; P = 0.011), ratio of total–high-density lipoprotein (HDL) cholesterol (mean difference in change, −0.44 [CI, −0.71 to −0.16]; P = 0.002), and triglyceride level (mean difference in change, −0.16 mmol/L [−14.1 mg/dL] [CI, −0.31 to −0.01 mmol/L {−27.4 to −0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P < 0.001) than those on the low-fat diet.

Limitation: Lack of clinical cardiovascular disease end points.

Conclusion: The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.

Primary Funding Source: National Institutes of Health

A Non-calorie-restricted Low-carbohydrate Diet is Effective as an Alternative Therapy for Patients with Type 2 Diabetes

Objective Although caloric restriction is a widely used intervention to reduce body weight and insulin resistance, many patients are unable to comply with such dietary therapy for long periods. The clinical effectiveness of low-carbohydrate diets was recently described in a position statement of Diabetes UK and a scientific review conducted by the American Diabetes Association. However, randomised trials of dietary interventions in Japanese patients with type 2 diabetes are scarce. Therefore, the aim of this study was to examine the effects of a non-calorie-restricted, low-carbohydrate diet in Japanese patients unable to adhere to a calorie-restricted diet.
Methods The enrolled patients were randomly allocated to receive a conventional calorie-restricted diet or low-carbohydrate diet. The patients received consultations every two months from a registered dietician for six months. We compared the effects of the two dietary interventions on glycaemic control and metabolic profiles.
Results The HbA1c levels decreased significantly from baseline to six months in the low-carbohydrate diet group (baseline 7.6±0.4%, six months 7.0±0.7%, p=0.03) but not in the calorie-restricted group (baseline 7.7±0.6%, six months 7.5±1.0%, n.s.), (between-group comparison, p=0.03). The patients in the former group also experienced improvements in their triglyceride levels, without experiencing any major adverse effects or a decline in the quality of life.
Conclusion Our findings suggest that a low-carbohydrate diet is effective in lowering the HbA1c and triglyceride levels in patients with type 2 diabetes who are unable to adhere to a calorie-restricted diet.

Renal Function Following Three Distinct Weight Loss Dietary Strategies During 2Years of a Randomized Controlled Trial

OBJECTIVE:
This study addressed the long-term effect of various diets, particularly low-carbohydrate high-protein, on renal function on participants with or without type 2 diabetes.
RESEARCH DESIGN AND METHODS:
In the 2-year Dietary Intervention Randomized Controlled Trial (DIRECT), 318 participants (age, 51 years; 86% men; BMI, 31 kg/m(2); mean estimated glomerular filtration rate [eGFR], 70.5 mL/min/1.73 m(2); mean urine microalbumin-to-creatinine ratio, 12:12) with serum creatinine <176 μmol/L (eGFR ≥ 30 mL/min/1.73 m(2)) were randomized to low-fat, Mediterranean, or low-carbohydrate diets. The 2-year compliance was 85%, and the proportion of protein intake significantly increased to 22% of energy only in the low-carbohydrate diet (P < 0.05 vs. low-fat and Mediterranean). We examined changes in urinary microalbumin and eGFR, estimated by Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration formulas.
RESULTS:
Significant (P < 0.05 within groups) improvements in eGFR were achieved in low-carbohydrate (+5.3% [95% CI 2.1-8.5]), Mediterranean (+5.2% [3.0-7.4]), and low-fat diets (+4.0% [0.9-7.1]) with similar magnitude (P > 0.05) across diet groups. The increased eGFR was at least as prominent in participants with (+6.7%) or without (+4.5%) type 2 diabetes or those with lower baseline renal function of eGFR <60 mL/min/1.73 m(2) (+7.1%) versus eGFR ≥ 60 mL/min/1.73 m(2) (+3.7%). In a multivariable model adjusted for age, sex, diet group, type 2 diabetes, use of ACE inhibitors, 2-year weight loss, and change in protein intake (confounders and univariate predictors), only a decrease in fasting insulin (β = -0.211; P = 0.004) and systolic blood pressure (β = -0.25; P < 0.001) were independently associated with increased eGFR. The urine microalbumin-to-creatinine ratio improved similarly across the diets, particularly among participants with baseline sex-adjusted microalbuminuria, with a mean change of -24.8 (P < 0.05).
CONCLUSIONS:
A low-carbohydrate diet is as safe as Mediterranean or low-fat diets in preserving/improving renal function among moderately obese participants with or without type 2 diabetes, with baseline serum creatinine <176 μmol/L. Potential improvement is likely to be mediated by weight loss-induced improvements in insulin sensitivity and blood pressure.

Use of the modified Atkins diet for treatment of refractory childhood epilepsy: A randomized controlled trial

PURPOSE:
The aim of this study was to evaluate the efficacy of the modified Atkins diet in a randomized controlled trial in children with refractory epilepsy.
METHODS:
Children aged 2-14 years who had daily seizures despite the appropriate use of at least three anticonvulsant drugs were enrolled. Children were randomized to receive either the modified Atkins diet or no dietary intervention for a period of 3 months. The ongoing anticonvulsant medications were continued unchanged in both the groups. Seizure control at 3 months was the primary end point. Analysis was intention to treat. Adverse effects of the diet were assessed by parental reports (ClinicalTrials.gov Identifier: NCT00836836).
KEY FINDINGS:
Among a total of 102 children, 50 were in the diet group and 52 in the control group. Four children discontinued the diet before the study end point, and three children in the control group were lost to follow-up. The mean seizure frequency at 3 months, expressed as a percentage of the baseline, was significantly less in the diet group: 59 ± 54 (95% confidence interval [CI] 44-74.5) versus 95.5 ± 48 (95% CI 82-109), p = 0.003. The proportion of children with >90% seizure reduction (30% vs. 7.7%, p = 0.005) and >50% seizure reduction was significantly higher in the diet group (52% vs. 11.5%, p < 0.001). Constipation was the most common adverse effect among children on the diet (23, 46%).
SIGNIFICANCE:
The modified Atkins diet was found to be effective and well tolerated in children with drug-refractory epilepsy.

Consuming a hypocaloric high fat low carbohydrate diet for 12 weeks lowers C-reactive protein, and raises serum adiponectin and high density lipoprotein-cholesterol in obese subjects

OBJECTIVE:
High fat, low carbohydrate (HFLC) diets have become popular tools for weight management. We sought to determine the effects of a HFLC diet compared to a low fat high carbohydrate (LFHC) diet on the change in weight loss, cardiovascular risk factors and inflammation in subjects with obesity.
METHODS:
Obese subjects (29.0-44.6 kg/m2) recruited from Boston Medical Center were randomized to a hypocaloric LFHC (n=26) or HFLC (n=29) diet for 12 weeks.
RESULTS:
The age range of subjects was 21-62 years. As a percentage of daily calories, the HFLC group consumed 33.5% protein, 56.0% fat and 9.6% carbohydrate and the LFHC group consumed 22.0% protein, 25.0% fat and 55.7% carbohydrate. The change in percent body weight, lean and fat mass, blood pressure, flow mediated dilation, hip:waist ratio, hemoglobin A1C, fasting insulin and glucose, and glucose and insulin response to a 2h oral glucose tolerance test did not differ (P>0.05) between diets after 12 weeks. The HFLC group had greater mean decreases in serum triglyceride (P=0.07), and hs-CRP (P=0.03), and greater mean increases in HDL cholesterol (P=0.004), and total adiponectin (P=0.045) relative to the LFHC. Secreted adipose tissue adiponectin or TNF-α did not differ after weight loss for either diet.
CONCLUSIONS:
Relative to the LFHC group, the HFLC group had greater improvements in blood lipids and systemic inflammation with similar changes in body weight and composition. This small-scale study suggests that HFLC diets may be more beneficial to cardiovascular health and inflammation in free-living obese adults compared to LFHC diets.

Long Term Successful Weight Loss with a Combination Biphasic Ketogenic Mediterranean Diet and Mediterranean Diet Maintenance Protocol

Weight loss protocols can only be considered successful if they deliver consistent results over the long term—a goal which is often elusive, so much so that the term “yo-yo” is used to describe the perennial weight loss/weight regain battle common in obesity. We hypothesized that a ketogenic Mediterranean diet with phytoextracts (KEMEPHY) combined with the acknowledged health benefits of traditional Mediterranean nutrition may favor long term weight loss. We analysed 89 male and female obese subjects, aged between 25 and 65 years who were overall healthy apart from being overweight. The subjects followed a staged diet protocol over a period of 12 months: 20 day of KEMEPHY; 20 days low carb-non ketogenic; 4 months Mediterranean normocaloric nutrition; a second 20 day
ketogenic phase followed by 6 months of Mediterranean normocaloric nutrition. For the majority of subjects (88.25%) there was significant loss of weight (from 100.7 ± 16.54 to 84.59 ± 9.71 kg; BMI from 35.42 ± 4.11 to 30.27 ± 3.58) and body fat (form 43.44% ± 6.34% to 33.63% ± 7.6%) during both ketogenic phases followed by successful maintenance, without weight regain, during the 6 month stabilization phase with only 8 subjects failing to comply. There were also significant and stable decreases in total cholesterol, LDLc, triglycerides and glucose levels over the 12 month study period. HDLc showed small increases after the ketogenic phases but over the full 12 months there was no significant change. No significant changes were observed in ALT, AST, Creatinine or BUN. The combination of a biphasic KEMEPHY diet separated by longer periods of maintenance nutrition, based on the traditional Mediterranean diet, led to successful long term weight loss and improvements in health risk factors in a majority of subjects; compliance was very high which was a key determinant of the results seen.

Saturated fat is not the major issue

Scientists universally accept that trans fats—found in many fast foods, bakery products, and margarines—increase the risk of cardiovascular disease through inflammatory processes.1 But “saturated fat” is another story. The mantra that saturated fat must be removed to reduce the risk of cardiovascular disease has dominated dietary advice and guidelines for almost four decades.

Yet scientific evidence shows that this advice has, paradoxically, increased our cardiovascular risks. Furthermore, the government’s obsession with levels of total cholesterol, which has led to the overmedication of millions of people with statins, has diverted our attention from the more egregious risk factor of atherogenic dyslipidaemia.

A decade of the modified Atkins diet (2003–2013): Results, insights, and future directions

The modified Atkins diet has been used since 2003 for the treatment of children and adults with refractory epilepsy.This “alternative” ketogenic diet is started in clinic, without fasting, hospitalization, and restriction of protein,calories, or fluid intake. Now after 10 years of continued use, approximately 400 patients have been reported in over 30 studies of the modified Atkins diet as treatment for intractable seizures, with results demonstrating similar efficacy to the ketogenic diet and improved tolerability. The modified Atkins diet is being increasingly used in the adult population. Clinical trials have provided insight into the mechanisms of action of dietary therapies overall. This review will discuss the past decade of experience with the modified Atkins diet as well as predictions for its role in the treatment of epilepsy a decade from now.