Surender K Arora and Samy I McFarlane. The case for low carbohydrate diets in diabetes management. Nutrition & Metabolism 2005, 2:16 doi:10.1186/1743-7075-2-16
A low fat, high carbohydrate diet in combination with regular exercise is the traditional recommendation for treating diabetes. Compliance with these lifestyle modifications is less than satisfactory, however, and a high carbohydrate diet raises postprandial plasma glucose and insulin secretion, thereby increasing risk of CVD, hypertension, dyslipidemia, obesity and diabetes. Moreover, the current epidemic of diabetes and obesity has been, over the past three decades, accompanied by a significant decrease in fat consumption and an increase in carbohydrate consumption.
This apparent failure of the traditional diet, from a public health point of view, indicates that alternative dietary approaches are needed. Because carbohydrate is the major secretagogue of insulin, some form of carbohydrate restriction is a prima facie candidate for dietary control of diabetes.
Evidence from various randomized controlled trials in recent years has convinced us that such diets are safe and effective, at least in short-term. These data show low carbohydrate diets to be comparable or better than traditional low fat high carbohydrate diets for weight reduction, improvement in the dyslipidemia of diabetes and metabolic syndrome as well as control of blood pressure, postprandial glycemia and insulin secretion. Furthermore, the ability of low carbohydrate diets to reduce triglycerides and to increase HDL is of particular importance.
Resistance to such strategies has been due, in part, to equating it with the popular Atkins diet. However, there are many variations and room for individual physician planning. Some form of low carbohydrate diet, in combination with exercise, is a viable option for patients with diabetes. However, the extreme reduction of carbohydrate of popular diets (<30g/day) cannot be recommended for a diabetic population at this time without further study.
On the other hand, the dire objections continually raised in the literature appear to have very little scientific basis. Whereas it is traditional to say that more work needs to be done, the same is true of the assumed standard low fat diets which have an ambiguous record at best. We see current trends in the national dietary recommendations as a positive sign and an appropriate move in the right direction
How Low-Carb Diets Benefit Obese Diabetics
Boden G, Sargrad K, Homko C, Mozzoli M, Stein TP. Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes. Ann Intern Med 2005; 142: 403-411
Temple University School of Medicine, Philadelphia, Pennsylvania, and University of Medicine and Dentistry of New Jersey School of Osteopathic Medicine, Stratford, New Jersey.
BACKGROUND: It is not known how a low-carbohydrate, high-protein, high-fat diet causes weight loss or how it affects blood glucose levels in patients with type 2 diabetes.
OBJECTIVE: To determine effects of a strict low-carbohydrate diet on body weight, body water, energy intake and expenditure, glycemic control, insulin sensitivity, and lipid levels in obese patients with type 2 diabetes.
DESIGN: Inpatient comparison of 2 diets.
SETTING: General clinical research center of a university hospital.
PATIENTS: 10 obese patients with type 2 diabetes.
INTERVENTION: Usual diets for 7 days followed by a low-carbohydrate diet for 14 days.
MEASUREMENTS: Body weight, water, and composition; energy intake and expenditure; diet satisfaction; hemoglobin A1c; insulin sensitivity; 24-hour urinary ketone excretion; and plasma profiles of glucose, insulin, leptin, and ghrelin.
RESULTS: On the low-carbohydrate diet, mean energy intake decreased from 3111 kcal/d to 2164 kcal/d. The mean energy deficit of 1027 kcal/d (median, 737 kcal/d) completely accounted for the weight loss of 1.65 kg in 14 days (median, 1.34 kg in 14 days). Mean 24-hour plasma profiles of glucose levels normalized, mean hemoglobin A1c decreased from 7.3% to 6.8%, and insulin sensitivity improved by approximately 75%. Mean plasma triglyceride and cholesterol levels decreased (change, -35% and -10%, respectively).
LIMITATIONS: The study was limited by the short duration, small number of participants, and lack of a strict control group.
CONCLUSION: In a small group of obese patients with type 2 diabetes, a low-carbohydrate diet followed for 2 weeks resulted in spontaneous reduction in energy intake to a level appropriate to their height; weight loss that was completely accounted for by reduced caloric intake; much improved 24-hour blood glucose profiles, insulin sensitivity, and hemoglobin A1c; and decreased plasma triglyceride and cholesterol levels. The long-term effects of this diet, however, remain uncertain.
So just 2 weeks on a low-carbohydrate diet can lower blood pressure, improve blood-sugar control and reduce levels of blood fats and cholesterol in obese individuals with Type 2 diabetes.
"When we took away the carbohydrates, the patients spontaneously reduced their daily energy consumption by 1000 calories a day," said lead researcher Dr Guenther Boden, from Temple University School of Medicine in Philadelphia, Pennsylvania. Importantly, patients did not compensate by eating more protein or fat. "The carbohydrates were clearly stimulating their excessive appetites," he said.
Participants,who were very obese, with an average body mass index of more than 40 kg/m2, stayed at a research centre for the duration of the study, eating their usual diet for the first 7 days, then following a low-carbohydrate diet, which included about 21 g of carbohydrates per day, for the next 14 days.
This is yet another study that supports a low-carb diet for diabetics. There have been so many studies showing this over the past half century that I wonder just how many more we need before the Diabetes establishment actually wakes up and stops harming people with their '5 a day' nonsense!
The authors remark that the long-term effects are uncertain, yet there are reams of evidence that the only effects are beneficial.