Many current popular weight-loss diets advocate restricting carbohydrates, but risks and benefits of these diets for patients with diabetes is unclear. We searched for articles published in English between 1980 and April 2006 regarding carbohydrate-restricted diets that included and reported separate results for adult, nonpregnant patients with type 2 diabetes. Articles were limited to studies completed in the United States and Canada. Available data on study design; carbohydrate composition of diet; duration of diet; and the outcomes of weight, lipid levels (total, low-density lipoprotein and high-density lipoprotein cholesterol, and triglycerides), hemoglobin A1c percent and/or fasting glucose were extracted. A total of 56 studies or reviews were evaluated. Thirteen studies met our inclusion criteria. Meta-regression analyses show that hemoglobin A1c, fasting glucose, and some lipid fractions (triglycerides) improved with lower carbohydrate−content diets. Overall effect on weight was equivocal among the studies evaluated in this meta-analysis. Randomized, controlled studies of restricted-carbohydrate diets in patients with diabetes need to be conducted in order to evaluate the overall sustainability of outcomes and long-term safety.
Section snippets
Literature Search and Study Selection
We conducted a MEDLINE search in PubMed, Cumulative Index to Nursing and Allied Health, Combined Health Information Database, Cochrane Library, and Web of Science using Medical Subject Heading from 1980 through April 2006. We utilized the medical subject heading term diabetes mellitus, type 2 and combined it with the medical subject heading term, dietary carbohydrates. We retrieved abstracts of English-language studies in people aged 19 years of age and older, comparing restricted-carbohydrate
Results
Our search resulted in 329 articles; 56 contained information regarding carbohydrate content and type 2 diabetes (Figure 1). Thirteen published studies (Table 1) fulfilled our inclusion criteria (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32). Some investigators published studies from the same data set, and the most comparable data set to other studies included in this meta-analysis was utilized (28, 29, 32, 33, 34, 35). A summary description of the designs for all 13 studies included in
Discussion
This meta-analysis indicates that lower-carbohydrate diets can be beneficial in treating type 2 diabetes, not only because of improved glycemic control, but also because of potential salutary changes in the lipid profile. Improvements in fasting glucose, HbA1c, and triglycerides appear to result from even moderate decreases in carbohydrate intake. For example, based on the meta-analysis regression model for triglycerides, a decrease in carbohydrate intake from 65% to 35% shows an expected
Summary
Diabetes mellitus is, in part, a disorder of carbohydrate metabolism that results in hyperglycemia. Carbohydrates are the component of the diet that exerts the greatest influence on postprandial blood glucose (41). Thus, it is logical that diets lower in carbohydrates would result in less hyperglycemia. Use of a balanced diet, exercise, and blood glucose−lowering medication should be combined to achieve glycemic control and a healthy weight. Results of our meta-analysis suggest short-term use
J. K. Kirk is an associate professor and D. E. Graves is a diabetes educator, Department of Family and Community Medicine, Wake Forest University School of Medicine, and T. E. Craven is a Biostatistician IV, Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC.
Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: A randomized trial
JAMA
(2005)
S. Klein et al.
Weight management through lifestyle modification for the prevention and management of type 2 diabetes: Rationale and strategies: A statement of the American Diabetes Association, the North American Association for the Study of Obesity, and the American Society for Clinical Nutrition
Diabetes Care
(2004)
A. Avenell et al.
What are the long-term benefits of weight reducing diets in adults?A systematic review of randomized controlled trials
J Hum Nutr Diet
(2004)
J.W. Anderson et al.
Carbohydrate and fiber recommendations for individuals with diabetes: A quantitative assessment and meta-analysis of the evidence
J Am Coll Nutr
(2004)
H. Moore et al.
Dietary advice for treatment of type 2 diabetes mellitus in adults
Cochrane Database Syst Rev
(2004)
S.K. Arora et al.
The case for low carbohydrate diets in diabetes management
Nutr Metab
(2005)
R.L. Kennedy et al.
Nutrition in patients with type 2 diabetes: Are low-carbohydrate diets effective, safe or desirable?
Diabet Med
(2005)
D.M. Bravata et al.
Efficacy and safety of low-carbohydrate diets: A systematic review
JAMA
(2003)
A.J. Nordmann et al.
Effects of low-carbohydrate vs low-fat diets on weight loss and cardiovascular risk factors: A meta-analysis of randomized controlled trials
Arch Intern Med
(2006)
N.F. Sheard et al.
Dietary carbohydrate (amount and type) in the prevention and management of diabetes: A statement by the American Diabetes Association
Diabetes Care
(2004)
T.C. Crowe
Safety of low-carbohydrate diets
Obes Rev
(2005)
J. Nielsen et al.
Lasting improvement of hyperglycaemia and bodyweight: Low-carbohydrate diet in type 2 diabetesA brief report
Ups J Med Sci
(2005)
B. Parker et al.
Effect of a high-monounsaturated fat weight loss diet on glycemic control and lipid levels in type 2 diabetes
Diabetes Care
(2002)
G.D. Brinkworth et al.
Long-term effects of advise to consume a high-protein, low-fat diet rather than a conventional weight-loss diet, in obese adults with type 2 diabetes: A one year follow-up of a randomised trial
Diabetologia
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Effect of a high-protein, low-carbohydrate diet on blood glucose control in people with type 2 diabetes
The development or remission of diet-induced overweight type 2 diabetes involves many biological changes which occur over very different timescales. Remission, defined by , or fasting plasma glucose concentration mg/dl, may be achieved rapidly by following weight loss guidelines. However, remission is often short-term, followed by relapse. Mathematical modelling provides a way of investigating a typical situation, in which patients are advised to lose weight and then maintain fat mass, a slow variable. Remission followed by relapse, in a modelling sense, is equivalent to changing from a remission trajectory with steady state mg/dl, to a relapse trajectory with steady state mg/dl. Modelling predicts that a trajectory which maintains weight will be a relapse trajectory, if the fat mass chosen is too high, the threshold being dependent on the lipid to carbohydrate ratio of the diet. Modelling takes into account the effects of hepatic and pancreatic lipid on hepatic insulin sensitivity and -cell function, respectively. This study leads to the suggestion that type 2 diabetes remission guidelines be given in terms of model parameters, not variables; that is, the patient should adhere to a given nutrition and exercise plan, rather than achieve a certain subset of variable values. The model predicts that calorie restriction, not weight loss, initiates remission from type 2 diabetes; and that advice of the form ‘adhere to the diet and exercise plan’ rather than ‘achieve a certain weight loss’ may help counter relapse.
2023, Industrial Application of Functional Foods, Ingredients and Nutraceuticals: Extraction, Processing and Formulation of Bioactive Compounds
Diabetes is a widespread epidemic affecting millions of people each year. The association between diabetes and obesity is not a tale that is waiting to be told. The idea of this chapter is to highlight the importance of early control and to understand the complications of the disease and associated comorbidities. Diabetes and obesity is not only an issue of concern amongst adults now but also huge problem among children. With the increase in the sedentary lifestyle amongst the population and consumption of high-fat foods, the graph of this epidemic sees no fall. A combination of diabetes and obesity is an invitation to many other disorders, not only physical but also psychological.
With the prevalence of diabetes worldwide, it is urgent to find a suitable treatment. Recently, the ketogenic diet has shown beneficial effects in reducing blood glucose, but some concerns have been raised about its probable side effects, such as hyperlipidemia and hepatic steatosis. Because a low-carbohydrate diet replaces part of the fat with carbohydrates on the basis of the ketogenic diet, we would like to know whether it does better in treating type 2 diabetes. The aim of this study was to explore the possibility of a low-carbohydrate diet as a substitute for a ketogenic diet intervention in mice with type 2 diabetes.
C57 BL/6 J mice with type 2 diabetes, constructed by a high-fat diet combined with streptozotocin, were fed a standard diet, a high-fat diet, a low-carbohydrate diet, or a ketogenic diet for 14 wk, respectively. Then glucose and insulin tolerance tests were conducted. At the end of the study, blood and liver samples were collected and analyzed for serum biochemical indicators, histopathologic evaluation, hepatic lipid and glycogen content, and expression levels of mRNA and protein.
Reduced blood glucose could be observed in both low-carbohydrate and ketogenic diets, as well as improvement in glucose tolerance and insulin sensitivity. However, the ketogenic diet decreased liver glycogen content and promoted gluconeogenesis. Mechanistically, this effect was due to inhibition of phosphorylated AMP-activated protein kinase, which could be improved by a low-carbohydrate diet. Regarding lipid metabolism, the ketogenic diet increased lipid oxidation and reduced de novo lipogenesis, but the hepatic lipid content still inevitably increased. On the contrary, the low-carbohydrate diet reduced triacylglycerols and markers of liver damage.
Collectively, these findings suggest that both diets are effective in lowering blood glucose, improving glucose tolerance, and raising insulin sensitivity. Moreover, the low-carbohydrate diet plays a role in inhibiting hepatic gluconeogenesis and improving lipid metabolism. The results suggest that the two diets have different effects on glucose and lipid metabolism, and that the low-carbohydrate diet might have more benefits in the treatment of type 2 diabetes mellitus.
Ketogenic diets (KD), very low carbohydrate diets which evoke nutritional ketosis, have been a popular weight loss strategy for decades.1 KDs are also becoming increasingly popular with diabetes patients2,3 and healthcare professionals,4,5 due to their efficacy in reducing HbA1c and body weight, as well as improving lipid profiles.6–8 However, KDs have been associated with increased frequency of hypoglycemia in T1DM9 and T2DM.7
Ketogenic diets (KDs) are becoming increasingly popular for the treatment of diabetes, yet they are associated with increased frequency of hypoglycemia. Here we report that mice fed a KD display blunted glucagon release to hypoglycemia and neuroglucopenia, suggesting that consuming a KD may increase the risk for iatrogenic hypoglycemia.
J. K. Kirk is an associate professor and D. E. Graves is a diabetes educator, Department of Family and Community Medicine, Wake Forest University School of Medicine, and T. E. Craven is a Biostatistician IV, Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC.
E. W. Lipkin is an associate professor of Medicine, University of Washington, Seattle.
M. Austin is principal, The Austin Group, LLC, Shelby Township, MI.
K. L. Margolis is a senior clinical investigator, HealthPartners Research Foundation, Minneapolis, MN.
