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Diabetes

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1: Aust Fam Physician. 2006 Jun;35(6):411-3. Related Articles, Links
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High protein diets and diabetes.

Carapetis M, Phillips PJ.

Diabetes Centre, The Queen Elizabeth Hospital, South Australia. melissa.carapetis@nwahs.sa.gov.au

Higher protein diets are currently 'hot'. The CSIRO total wellbeing diet book has been on the bestseller list in Australia and internationally. Various other high protein diets have also had, or are getting, media attention. However, high protein diets, particularly for people with diabetes, are controversial. There are questions about effectiveness and safety, especially in the long term. As a general practitioner people will look to you for advice about what to eat. This article summarises the pros and cons of two of the popular higher protein diets--the Atkins diet and the CSIRO total wellbeing.

PMID: 16751857 [PubMed - indexed for MEDLINE]
 
2: Diabetologia. 2005 Jan;48(1):8-16. Epub 2004 Dec 23. Related Articles, Links
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Erratum in:
  • Diabetologia. 2005 May;48(5):1033.


Comment in:


Comparison of high-fat and high-protein diets with a high-carbohydrate diet in insulin-resistant obese women.

McAuley KA, Hopkins CM, Smith KJ, McLay RT, Williams SM, Taylor RW, Mann JI.

Edgar National Centre for Diabetes Research, Medical and Surgical Sciences, University of Otago, PO Box 56, Dunedin, New Zealand. kirsten.mcauley@stonebow.otago.ac.nz

AIMS/HYPOTHESIS: A diet low in saturated fatty acids and rich in wholegrains, vegetables and fruit is recommended in order to reduce the risk of obesity, cardiovascular disease and type 2 diabetes mellitus. However there is widespread interest in high-fat ("Atkins Diet") and high-protein ("Zone Diet") alternatives to the conventional high-carbohydrate, high-fibre approach. We report on a randomised trial that compared these two alternative approaches with a conventional diet in overweight insulin-resistant women. METHODS: Ninety-six normoglycaemic, insulin-resistant women (BMI >27 kg/m(2)) were randomised to one of three dietary interventions: a high-carbohydrate, high-fibre (HC) diet, the high-fat (HF) Atkins Diet, or the high-protein (HP) Zone Diet. The experimental approach was designed to mimic what might be achieved in clinical practice: the recommendations involved advice concerning food choices and were not prescriptive in terms of total energy. There were supervised weight loss and weight maintenance phases (8 weeks each), but there was no contact between the research team and the participants during the final 8 weeks of the study. Outcome was assessed in terms of body composition and indicators of cardiovascular and diabetes risk. RESULTS: Body weight, waist circumference, triglycerides and insulin levels decreased with all three diets but, apart from insulin, the reductions were significantly greater in the HF and HP groups than in the HC group. These observations suggest that the popular diets reduced insulin resistance to a greater extent than the standard dietary advice did. When compared with the HC diet, the HF and HP diets were shown to produce significantly (p<0.01) greater reductions in several parameters, including weight loss (HF -2.8 kg, HP -2.7 kg), waist circumference (HF -3.5 cm, HP -2.7 cm) and triglycerides (HF -0.30 mmol/l, HP [corrected] -0.22 mmol/l). LDL cholesterol decreased in individuals on the HC and HP diets, but tended to fluctuate in those on the HF diet to the extent that overall levels were significantly lower in the HP group than in the HF group (-0.28 mmol/l, 95% CI 0.04-0.52, p=0.02). Of those on the HF diet, 25% showed a >10% increase in LDL cholesterol, whereas this occurred in only 13% of subjects on the HC diet and 3% of those on the HP diet. CONCLUSIONS/INTERPRETATION: In routine practice a reduced-carbohydrate, higher protein diet may be the most appropriate overall approach to reducing the risk of cardiovascular disease and type 2 diabetes. To achieve similar benefits on a HC diet, it may be necessary to increase fibre-rich wholegrains, legumes, vegetables and fruits, and to reduce saturated fatty acids to a greater extent than appears to be achieved by implementing current guidelines. The HF approach appears successful for weight loss in the short term, but lipid levels should be monitored. The potential deleterious effects of the diet in the long term remain a concern.

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PMID: 15616799 [PubMed - indexed for MEDLINE]

 
3: J Am Diet Assoc. 2005 Apr;105(4):573-80. Related Articles, Links
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Effect of high protein vs high carbohydrate intake on insulin sensitivity, body weight, hemoglobin A1c, and blood pressure in patients with type 2 diabetes mellitus.

Sargrad KR, Homko C, Mozzoli M, Boden G.

Nutrition Center, Department of Bioscience and Biotechnology, Drexel University, Philadelphia, PA 19104, USA. ksargrad@drexel.edu

BACKGROUND: Extremely low carbohydrate/high protein diets are popular methods of weight loss. Compliance with these diets is poor and long-term effectiveness and the safety of these diets for patients with type 2 diabetes is not known. OBJECTIVE: The objective of the current study was to evaluate effects of less extreme changes in carbohydrate or protein diets on weight, insulin sensitivity, glycemic control, cardiovascular risk factors (blood pressure, lipid levels), and renal function in obese inner-city patients with type 2 diabetes. DESIGN: Study patients were admitted to the General Clinical Research Center for 24 hours for initial tests including a hyperinsulinemic-euglycemic clamp (for measurement of insulin sensitivity), bioelectrical impedance analysis (BIA) and anthropometric measurements (for assessment of body composition), indirect calorimetry (for measurement of REE), electronic blood pressure monitoring, and blood chemistries to measure blood lipids levels along with renal and hepatic functions. Six patients with type 2 diabetes (five women and one man) were randomly assigned to the high-protein diet (40% carbohydrate, 30% protein, 30% fat) and six patients (four women and two men) to the high-carbohydrate diet (55% carbohydrate, 15% protein, 30% fat). All patients returned to the General Clinical Research Center weekly for monitoring of food records; dietary compliance; and measurements of body weight, blood pressure, and blood glucose. After 8 weeks on these diets, all patients were readmitted to the General Clinical Research Center for the same series of tests. INTERVENTION: Twelve study patients were taught to select either the high-protein or high-carbohydrate diet and were followed for 8 weeks. MAIN OUTCOME MEASURES: Insulin sensitivity, hemoglobin A1c, weight, and blood pressure were measured. STATISTICAL ANALYSES: Statistical significance was assessed using two-tailed Student's t tests and two-way repeated measures analysis of variance. RESULTS: Both the high-carbohydrate and high-protein groups lost weight (-2.2+/-0.9 kg, -2.5+/-1.6 kg, respectively, P <.05) and the difference between the groups was not significant (P =.9). In the high-carbohydrate group, hemoglobin A1c decreased (from 8.2% to 6.9%, P <.03), fasting plasma glucose decreased (from 8.8 to 7.2 mmol/L, P <.02), and insulin sensitivity increased (from 12.8 to 17.2 micromol/kg/min, P <.03). No significant changes in these parameters occurred in the high-protein group, instead systolic and diastolic blood pressures decreased (-10.5+/-2.3 mm Hg, P =.003 and -18+/-9.0 mm Hg, P <.05, respectively). After 2 months on these hypocaloric diets, each diet had either no or minimal effects on lipid levels (total cholesterol, low-density lipoprotein, high-density lipoprotein), renal (blood urea nitrogen, serum creatinine), or hepatic function (aspartate aminotransferase, alanine aminotransferase, bilirubin).

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PMID: 15800559 [PubMed - indexed for MEDLINE]

 
4: Curr Diab Rep. 2002 Oct;2(5):457-64. Related Articles, Links

Protein and diabetes: much advice, little research.

Franz MJ.

Nutrition Concepts by Franz, Inc., 6635 Limerick Drive, Minneapolis, MN 55439, USA. MarionFranz@aol.com

In persons with diabetes, moderate hyperglycemia can contribute to an increased turnover of protein. To maintain body composition and nitrogen balance requires metabolic control and sufficient protein and energy intakes. However, because most adults eat at least 50% more protein than is required, people with diabetes appear to be protected from protein malnutrition when consuming a usual diet. Although nonessential amino acids undergo hepatic gluconeogenesis, peripheral glucose concentrations do not increase after protein ingestion. The fate of produced glucose is unknown. Protein does not contribute to sustained elevations of glucose levels, slow absorption of carbohydrate, or help in the treatment of hypoglycemia--advice often given to persons with diabetes. Protein is, however, just as potent a stimulant of insulin secretion as glucose. No long-term research is available to document that high-protein, low-carbohydrate diets are continued long-term or that weight lost initially is maintained better from these diets than from traditional weight loss diets. Furthermore, in persons with type 2 diabetes, weight loss is reported to be related to energy restriction and not to the protein-to-carbohydrate ratio of the diet.

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PMID: 12643172 [PubMed - indexed for MEDLINE]

 
5: Circulation. 2001 Oct 9;104(15):1869-74. Related Articles, Links
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Comment in:


Dietary protein and weight reduction: a statement for healthcare professionals from the Nutrition Committee of the Council on Nutrition, Physical Activity, and Metabolism of the American Heart Association.

St Jeor ST, Howard BV, Prewitt TE, Bovee V, Bazzarre T, Eckel RH; Nutrition Committee of the Council on Nutrition, Physical Activity, and Metabolism of the American Heart Association.

High-protein diets have recently been proposed as a "new" strategy for successful weight loss. However, variations of these diets have been popular since the 1960s. High-protein diets typically offer wide latitude in protein food choices, are restrictive in other food choices (mainly carbohydrates), and provide structured eating plans. They also often promote misconceptions about carbohydrates, insulin resistance, ketosis, and fat burning as mechanisms of action for weight loss. Although these diets may not be harmful for most healthy people for a short period of time, there are no long-term scientific studies to support their overall efficacy and safety. These diets are generally associated with higher intakes of total fat, saturated fat, and cholesterol because the protein is provided mainly by animal sources. In high-protein diets, weight loss is initially high due to fluid loss related to reduced carbohydrate intake, overall caloric restriction, and ketosis-induced appetite suppression. Beneficial effects on blood lipids and insulin resistance are due to the weight loss, not to the change in caloric composition. Promoters of high-protein diets promise successful results by encouraging high-protein food choices that are usually restricted in other diets, thus providing initial palatability, an attractive alternative to other weight-reduction diets that have not worked for a variety of reasons for most individuals. High-protein diets are not recommended because they restrict healthful foods that provide essential nutrients and do not provide the variety of foods needed to adequately meet nutritional needs. Individuals who follow these diets are therefore at risk for compromised vitamin and mineral intake, as well as potential cardiac, renal, bone, and liver abnormalities overall.

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PMID: 11591629 [PubMed - indexed for MEDLINE]

 
6: Cochrane Database Syst Rev. 2004;(3):CD004097. Related Articles, Links
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Update of:


Dietary advice for treatment of type 2 diabetes mellitus in adults.

Moore H, Summerbell C, Hooper L, Cruickshank K, Vyas A, Johnstone P, Ashton V, Kopelman P.

Postgraduate Institute, University of Teesside, Parkside West Offices, School of Health and Social Care, University of Teesside, Middlesbrough, UK, TS1 3BA.

BACKGROUND: While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available. OBJECTIVES: To assess the effect of type and frequency of different types of dietary advice to all adults with type 2 diabetes on weight, measures of diabetic control, morbidity, total mortality and quality of life. SEARCH STRATEGY: We carried out a comprehensive search of The Cochrane Library (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October Week 1, 2003), EMBASE (1980 to Week 40, 2003), CINAHL (1982 to October Week 1, 2003), AMED (1985 to October 2003), bibliographies and contacted relevant experts. SELECTION CRITERIA: All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention in adults with type 2 diabetes mellitus. DATA COLLECTION AND ANALYSIS: The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data. For continuous outcomes, endpoint data were preferred to change data. MAIN RESULTS: Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias. REVIEWERS' CONCLUSIONS: There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

Publication Types:


PMID: 15266517 [PubMed - indexed for MEDLINE]

 
7: Cochrane Database Syst Rev. 2004;(2):CD004097. Related Articles, Links
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Update in:


Dietary advice for treatment of type 2 diabetes mellitus in adults.

Moore H, Summerbell C, Hooper L, Cruickshank K, Vyas A, Johnstone P, Ashton V, Kopelman P.

Postgraduate Institute, University of Teesside, Parkside West Offices, School of Health and Social Care, University of Teesside, Middlesbrough, UK, TS1 3BA.

BACKGROUND: While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available. OBJECTIVES: To assess the effect of type and frequency of different types of dietary advice to all adults with type 2 diabetes on weight, measures of diabetic control, morbidity, total mortality and quality of life. SEARCH STRATEGY: We carried out a comprehensive search of The Cochrane Library (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October Week 1, 2003), EMBASE (1980 to Week 40, 2003), CINAHL (1982 to October Week 1, 2003), AMED (1985 to October 2003), bibliographies and contacted relevant experts. SELECTION CRITERIA: All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention in adults with type 2 diabetes mellitus. DATA COLLECTION AND ANALYSIS: The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data. For continuous outcomes, endpoint data were preferred to change data. MAIN RESULTS: Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias. REVIEWERS' CONCLUSIONS: There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

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PMID: 15106237 [PubMed - indexed for MEDLINE]

 
8: J Clin Endocrinol Metab. 2004 Sep;89(9):4197-205. Related Articles, Links
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Diet, insulin resistance, and obesity: zoning in on data for Atkins dieters living in South Beach.

Lara-Castro C, Garvey WT.

Department of Nutrition Sciences, Webb 232, University of Alabama at Birmingham, 1675 University Boulevard, Birmingham, Alabama 35294-3360, USA.

Insulin resistance is a central pathogenic factor for the metabolic syndrome and is associated with both generalized obesity and the accumulation of fat in the omental and intramyocellular compartments. In the context of the current obesity epidemic, it is imperative to consider diets in terms of their ability to both promote weight loss and ameliorate insulin resistance. Weight loss under any dietary formulation depends on hypocaloric intake, and only moderate weight loss (5-10%) is sufficient to augment insulin sensitivity. However, increments in insulin sensitivity may be more directly related to loss of intramyocellular or omental fat rather than loss of total body weight per se. The widespread acceptance of popular low-carbohydrate high-fat diets (e.g. Atkins Diet, Zone Diet, South Beach diet) further underscores the need to evaluate dietary interventions regarding their safety and metabolic effects. These high-fat diets have been shown to be safe in the short term; however, their long-term safety has not been established. With respect to insulin sensitivity, diets enriched in saturated fats can induce insulin resistance, whereas fat substitution with monounsaturated fats can enhance insulin sensitivity. On the other hand, high-fiber, high-carbohydrate diets comprised of foods with low caloric density can similarly be used for effective weight reduction and to ameliorate insulin resistance. Although some data suggest that low-glycemic index diets are most advantageous in this regard, these effects may have more to do with increments in dietary fiber than differences in available carbohydrates. Popular low-carbohydrate, high-fat diets are being fervently embraced as an alternative to challenging modifications in lifestyle and intentional calorie reduction. Current data do not support such unbridled enthusiasm for these diets, particularly in relationship to high-fiber, high-carbohydrate diets emphasizing intake of fresh vegetables and fruits. Long-term studies to determine the efficacy and safety of both popular and experimental diets are warranted.

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PMID: 15356006 [PubMed - indexed for MEDLINE]

 
9: Diabetologia. 2004 Oct;47(10):1677-86. Epub 2004 Oct 6. Related Articles, Links
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Long-term effects of advice to consume a high-protein, low-fat diet, rather than a conventional weight-loss diet, in obese adults with type 2 diabetes: one-year follow-up of a randomised trial.

Brinkworth GD, Noakes M, Parker B, Foster P, Clifton PM.

Commonwealth Scientific Industrial and Research Organisation (CSIRO), Health Sciences and Nutrition, Adelaide, South Australia, Australia.

AIMS/HYPOTHESIS: This study compared the long-term weight loss and health outcomes at 1-year follow-up, after a 12-week intensive intervention consisting of two low-fat, weight-loss diets, which differed in protein content. METHODS: We randomly assigned 66 obese patients (BMI: 27-40 kg/m2) with type 2 diabetes to either a low-protein (15% protein, 55% carbohydrate) or high-protein diet (30% protein, 40% carbohydrate) for 8 weeks of energy restriction (approximately 6.7 MJ/day) and 4 weeks of energy balance. Subjects were asked to maintain the same dietary pattern for a further 12 months of follow-up. RESULTS: The study was completed by 38 of the subjects, with equal dropouts in each group. At Week 64, weight reductions against baseline were -2.2+/-1.1 kg (low protein) and -3.7+/-1.0 kg (high protein), p<0.01, with no diet effect. Fat mass was not different from baseline in either group. At Week 12, both diets reduced systolic and diastolic blood pressure by 6 and 3 mm Hg respectively, but blood pressure increased more with weight regain during follow-up in the low-protein group (p< or =0.04). At Week 64, both diets significantly increased HDL cholesterol and lowered C-reactive protein concentrations. There was no difference in the urinary urea : creatinine ratio at baseline between the two groups, but this ratio increased at Week 12 (in the high-protein group only, p<0.001, diet effect), remaining stable during follow-up in both diets. CONCLUSIONS/INTERPRETATION: A high-protein weight-reduction diet may in the long term have a more favourable cardiovascular risk profile than a low-protein diet with similar weight reduction in people with type 2 diabetes.

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PMID: 15480538 [PubMed - indexed for MEDLINE]

 
10: Diabetes Care. 1991 Dec;14(12):1126-31. Related Articles, Links

Dietary fiber--an overview.

Anderson JW, Akanji AO.

Metabolic Research Group, VA Medical Center, Lexington, KY 40511.

Diabetes diets should aim at ensuring an ideal body weight with normoglycemia and normolipidemia. The consensus recommendations of various diabetes associations suggest that these goals are most likely to be achieved by diets high in complex carbohydrates and fiber and low in fat. A typical diabetes diet containing 55-60% energy as carbohydrate (at least 66% complex), less than 30% energy as fat, 0.8 g.kg-1 desirable body wt.day-1 protein, and approximately 40 g fiber/day, improves glycemic control, reduces levels of serum atherogenic lipids, decreases blood pressure in those with hypertension, and reduces body weight in the obese. This diet also reduces insulin requirements in the insulin-treated patient and can promote discontinuation of insulin therapy in those with non-insulin-dependent diabetes mellitus. This article presents our experience with high-fiber high-carbohydrate diets and reviews knowledge on the likely mechanisms of action of fiber, its long-term effectiveness, and the concerns about its long-term safety. We suggest that reports on the risk of hypertriglyceridemia from on the risk of hypertriglyceridemia from high-carbohydrate diets are inconsistent and invalidated if those diets are also high in fiber content. Similarly, we urge some caution in prescribing high-monounsaturated fat diets as an alternative to high-carbohydrate diets, at least until the long-term implications of the former are clearer. We believe that there is no compelling reason to change the current diabetes diets, which should continue to be high in carbohydrate and fiber content.

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PMID: 1663444 [PubMed - indexed for MEDLINE]

 
11: J Am Coll Nutr. 2000 Oct;19(5):578-90. Related Articles, Links
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Health advantages and disadvantages of weight-reducing diets: a computer analysis and critical review.

Anderson JW, Konz EC, Jenkins DJ.

Veterans Affairs Medical Center, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington 40511, USA. jwandersmd@aol.com

BACKGROUND: Some weight-loss diets are nutritionally sound and consistent with recommendations for healthy eating while others are "fad" diets encouraging irrational and, sometimes, unsafe practices. OBJECTIVE: The purpose of the study was to compare several weight loss diets and assess their potential long-term effects. DESIGN: Eight popular weight-loss diets were selected (Atkins, Protein Power, Sugar Busters, Zone, ADA Exchange, High-Fiber Fitness, Pritikin and Omish) to be non-clinically analyzed by means of a computer to predict their relative benefits/potential harm. A summary description, menu plan and recommended snacks were developed for each diet. The nutrient composition of each diet was determined using computer software, and a Food Pyramid Score was calculated to compare diets. The Mensink, Hegsted and other formulae were applied to estimate coronary heart disease risk factors. RESULTS: Higher fat diets are higher in saturated fats and cholesterol than current dietary guidelines and their long-term use would increase serum cholesterol levels and risk for CHD. Diets restricted in sugar intake would lower serum cholesterol levels and long-term risk for CHD; however, higher carbohydrate, higher fiber, lower fat diets would have the greatest effect in decreasing serum cholesterol concentrations and risk of CHD. CONCLUSIONS: While high fat diets may promote short-term weight loss, the potential hazards for worsening risk for progression of atherosclerosis override the short-term benefits. Individuals derive the greatest health benefits from diets low in saturated fat and high in carbohydrate and fiber: these increase sensitivity to insulin and lower risk for CHD.

PMID: 11022871 [PubMed - indexed for MEDLINE]
 
12: Nutr Rev. 2002 Jul;60(7 Pt 1):189-200. Related Articles, Links
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High-protein weight-loss diets: are they safe and do they work? A review of the experimental and epidemiologic data.

Eisenstein J, Roberts SB, Dallal G, Saltzman E.

Energy Metabolism Lab, Jean Mayer USDA, Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.

Recommendations for increased consumption of protein are among the most common approaches of popular or fad diets. This review summarizes the effects of dietary protein on satiety, energy intake, thermogenesis, and weight loss, as well as its effect on a variety of health outcomes in adults. In short-term studies, dietary protein modulates energy intake via the sensation of satiety and increases total energy expenditure by increasing the thermic effect of feeding. Whereas these effects did not contribute to weight and fat loss in those studies in which energy intake was fixed, one ad libitum study does suggest that a high-protein diet results in a greater decrease in energy intake, and therefore greater weight and fat loss. In terms of safety, there is little long-term information on the health effects of high-protein diets. From the available data, however, it is evident that the consumption of protein greater than two to three times the U.S. Recommended Daily Allowance contributes to urinary calcium loss and may, in the long term, predispose to bone loss. Caution with these diets is recommended in those individuals who may be predisposed to nephrolithiasis or kidney disease, and particularly in those with diabetes mellitus.

Publication Types:


PMID: 12144197 [PubMed - indexed for MEDLINE]

 
13: Am J Clin Nutr. 2003 Oct;78(4):734-41. Related Articles, Links
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Comment in:


An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes.

Gannon MC, Nuttall FQ, Saeed A, Jordan K, Hoover H.

Metabolic Research Laboratory and the Section of Endocrinology, Metabolism, and Nutrition, Department of Veterans Affairs Medical Center, Minneapolis, Minnesota 55417, USA. ganno004@tc.umn.edu

BACKGROUND: In single-meal studies, dietary protein does not result in an increase in glucose concentrations in persons with or without type 2 diabetes, even though the resulting amino acids can be used for gluconeogenesis. OBJECTIVE: The metabolic effects of a high-protein diet were compared with those of the prototypical healthy (control) diet, which is currently recommended by several scientific organizations. DESIGN: The metabolic effects of both diets, consumed for 5 wk each (separated by a 2-5-wk washout period), were studied in 12 subjects with untreated type 2 diabetes. The ratio of protein to carbohydrate to fat was 30:40:30 in the high-protein diet and 15:55:30 in the control diet. The subjects remained weight-stable during the study. RESULTS: With the fasting glucose concentration used as a baseline from which to determine the area under the curve, the high-protein diet resulted in a 40% decrease in the mean 24-h integrated glucose area response. Glycated hemoglobin decreased 0.8% and 0.3% after 5 wk of the high-protein and control diets, respectively; the difference was significant (P < 0.05). The rate of change over time was also significantly greater after the high-protein diet than after the control diet (P < 0.001). Fasting triacylglycerol was significantly lower after the high-protein diet than after the control diet. Insulin, C-peptide, and free fatty acid concentrations were not significantly different after the 2 diets. CONCLUSION: A high-protein diet lowers blood glucose postprandially in persons with type 2 diabetes and improves overall glucose control. However, longer-term studies are necessary to determine the total magnitude of response, possible adverse effects, and the long-term acceptability of the diet.

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PMID: 14522731 [PubMed - indexed for MEDLINE]

 
14: J Nutr. 2004 Mar;134(3):586-91. Related Articles, Links
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High-protein, low-fat diets are effective for weight loss and favorably alter biomarkers in healthy adults.

Johnston CS, Tjonn SL, Swan PD.

Department of Nutrition, Arizona State University, Mesa, AZ 85212, USA. carol.johnston@asu.edu

Although popular and effective for weight loss, low-carbohydrate, high-protein, high-fat (Atkins) diets have been associated with adverse changes in blood and renal biomarkers. High-protein diets low in fat may represent an equally appealing diet plan but promote a more healthful weight loss. Healthy adults (n = 20) were randomly assigned to 1 of 2 low-fat (<30% energy), energy-restricted groups: high-protein (30% energy) or high-carbohydrate (60% energy); 24-h intakes were strictly controlled during the 6-wk trial. One subject from each group did not complete the trial due to out-of-state travel; two subjects in the high-carbohydrate group withdrew from the trial due to extreme hunger. Body composition and metabolic indices were assessed pre- and post-trial. Both diets were equally effective at reducing body weight (-6%, P < 0.05) and fat mass (-9 to -11%, P < 0.05); however, subjects consuming the high-protein diet reported more satisfaction and less hunger in mo 1 of the trial. Both diets significantly lowered total cholesterol (-10 to -12%), insulin (-25%), and uric acid (-22 to -30%) concentrations in blood from fasting subjects. Urinary calcium excretion increased 42% in subjects consuming the high-protein diet, mirroring the 50% increase in dietary calcium with consumption of this diet; thus, apparent calcium balance was not adversely affected. Creatinine clearance was not altered by diet treatments, and nitrogen balance was more positive in subjects consuming the high-protein diet vs. the high-carbohydrate diet (3.9 +/- 1.4 and 0.7 +/- 1.7 g N/d, respectively, P < 0.05). Thus, low-fat, energy-restricted diets of varying protein content (15 or 30% energy) promoted healthful weight loss, but diet satisfaction was greater in those consuming the high-protein diet.

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PMID: 14988451 [PubMed - indexed for MEDLINE]

 
15: Diabetes Care. 1991 Sep;14(9):774-85. Related Articles, Links

Effects of dietary carbohydrate and fat intake on glucose and lipoprotein metabolism in individuals with diabetes mellitus.

Hollenbeck CB, Coulston AM.

Department of Medicine, Stanford University School of Medicine, CA 94305.

The dietary treatment of individuals with diabetes remains a controversial issue. The major emphasis in recent years has been on the reduction of total fat and saturated fat and replacement with complex carbohydrate. The rationale for this approach is based on the premise that such diets will reduce the risk of coronary artery disease (CAD) by reducing total and low-density lipoprotein cholesterol concentrations. In this article, we review the available data and conclude that there is little evidence to support the notion that low-fat high-carbohydrate diets per se lead to any reduction in the risk for CAD in individuals with diabetes. The only data indicating that low-fat high-carbohydrate diets lead to beneficial effects on carbohydrate and lipoprotein metabolism are confounded either by the lack of suitable experimental control, by the fact that diets also differed in the type of dietary fat and amount of dietary cholesterol, or were enormously enriched in dietary fiber. When these factors are taken into consideration, there appears to be little evidence in support of the view that substituting carbohydrate for fat in the diets of individuals with diabetes results in any measurable beneficial effect. Indeed, it could be argued that the most characteristic defects in carbohydrate and lipoprotein metabolism are exacerbated in response to low-fat high-carbohydrate diets. Alternatively, the data presented herein strongly suggest that diets containing conventional quantities of fat, in which saturated fat is replaced by unsaturated fat and dietary cholesterol reduced, would result in the desired reductions to total and low-density lipoprotein cholesterol concentrations without the adverse effects of increased postprandial glucose and insulin concentrations, increased fasting and postprandial total and very-low-density lipoprotein triglyceride concentrations, and decreased fasting high-density lipoprotein cholesterol concentrations.

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PMID: 1959471 [PubMed - indexed for MEDLINE]

 
16: J Am Diet Assoc. 1989 Aug;89(8):1076-86. Related Articles, Links

The effects of diet differing in fat, carbohydrate, and fiber on carbohydrate and lipid metabolism in type II diabetes.

O'Dea K, Traianedes K, Ireland P, Niall M, Sadler J, Hopper J, De Luise M.

Department of Medicine (University of Melbourne) Repatriation General Hospital, Heidelberg, Victoria, Australia.

This study was designed to determine the effects of varying the proportions of carbohydrate, fiber, and fat on metabolic control in Type II diabetes. Ten men, aged 50 to 69 years, with Type II diabetes participated. Four isocaloric diets were consumed for 2 weeks each, with a break of 6 to 14 weeks between diets to ensure no carryover effects. Two of the diets were high in carbohydrate (63% to 65% energy) and low in fat (10% to 12% energy) but differed in their fiber contents (20 vs. 45 gm/day). The other two diets were low in carbohydrate (23% to 27% energy) with either a low or a high fat content (15% vs. 55% energy) and a high or normal protein content (62% vs. 18% energy). The composition of the subjects' usual diets in the week before each of the experimental diets did not vary significantly: carbohydrate 47% to 50% energy, protein 22% to 25% energy, fat 27% to 31% energy, and fiber 24 to 25 gm/day. A 75-gm oral glucose tolerance test and a 12-hour metabolic profile in response to 3 meals typical of the particular diet were conducted before and at the conclusion of each 2-week dietary period. The most significant improvements in metabolic control (as assessed by the effects of the diets on fasting glucose and on lipids, and on the glucose and insulin responses to oral glucose and the mixed meals) were obtained with the high-fiber, high-carbohydrate, low-fat diet and with the low-carbohydrate, high-protein, low-fat diet. Metabolic control was not significantly affected by the low-fiber, high-carbohydrate, low-fat diet, but it deteriorated significantly on the low-carbohydrate, high-fat diet. The results of this study confirmed the importance of high fiber and low fat in improving metabolic control in Type II diabetes. In conclusion, if high-carbohydrate, low-fat diets are to be recommended to patients with diabetes, it is essential that the type of carbohydrate recommended be unrefined and high in fiber.

PMID: 2547860 [PubMed - indexed for MEDLINE]
 
17: Diabetes Care. 1988 Feb;11(2):160-73. Related Articles, Links

Dietary fiber in management of diabetes.

Vinik AI, Jenkins DJ.

Department of Internal Medicine, University of Michigan, Ann Arbor.

Current evidence suggests that high-fiber diets, especially of the soluble variety, and soluble fiber supplements may offer some improvement in carbohydrate metabolism, lower total cholesterol and low-density lipoprotein (LDL) cholesterol, and have other beneficial effects in patients with non-insulin-dependent diabetes mellitus (NIDDM). Diets enriched with wheat bran and guar gum induce 10-20% reductions in serum cholesterol and LDL in both normo- and hypercholesterolemic subjects and have the ability to blunt the hypertriglyceridemic effects of diets high in carbohydrate and low in fiber. In insulin-dependent diabetes mellitus (IDDM) the situation is less clear, but a decrement of the circadian glucose profile has been shown. Americans, in general, consume too little fiber. With the need to restrict fat and reduce protein, an increase in carbohydrates is mandatory. A practical goal would be to establish the present level of fiber intake (15-30 g/day) and to gradually increase it. An intake of up to 40 g of fiber per day or 25 g/1000 kcal of food intake appears beneficial; in many individuals on weight-reducing diets higher levels may be unacceptable because of gastrointestinal side effects. The level of maximum benefit has not been determined. Fiber supplementation appears beneficial only if given with a diet comprising approximately half of the calories as carbohydrate. Foods should be selected with moderate to high amounts of dietary fiber from a wide variety of choices to include both soluble and insoluble types of fiber. Insufficient data are available on the long-term safety of high-fiber supplements. People at risk for deficiencies, such as postmenopausal women, the elderly, or growing children, may require supplements of calcium and trace minerals. People with upper gastrointestinal dysfunction are at risk of bezoar formation and cautioned against a diet high in fiber of the leafy vegetable type. Careful attention must be paid to insulin dose because hypoglycemia can result if there is a radical change in fiber intake and insulin dose is not reduced appropriately. Care must be exercised in the use of "novel" fibers, including the wood celluloses, because little is known of their safety and efficacy.

Publication Types:


PMID: 2838232 [PubMed - indexed for MEDLINE]

 
18: Diabetes Care. 1999 Jun;22(6):889-95. Related Articles, Links
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Comment in:


Effect of energy restriction, weight loss, and diet composition on plasma lipids and glucose in patients with type 2 diabetes.

Heilbronn LK, Noakes M, Clifton PM.

Department of Physiology, University of Adelaide, Australia. leonie.heilbronn@dhn.csiro.au

OBJECTIVE: To determine the optimal diet for improving glucose and lipid profiles in obese patients with type 2 diabetes during moderate energy restriction. RESEARCH DESIGN AND METHODS: A total of 35 free-living obese patients with type 2 diabetes were assigned to one of three 1,600 kcal/day diets for 12 weeks. The diets were high carbohydrate (10% fat, 4% saturated), high monounsaturated fat (MUFA) (32% fat, 7% saturated), or high saturated fat (SFA) (32% fat, 17% saturated). RESULTS: Diet composition did not affect the magnitude of weight loss, with subjects losing an average of 6.6 +/- 0.9 kg. Energy restriction and weight loss resulted in reductions in fasting plasma glucose (-14%), insulin (-27%), GHb (-14%), and systolic (-7%) and diastolic blood pressure (-10%) levels and the glucose response area (-17%) independent of diet composition. Diet composition did affect the lipoprotein profile. LDL was 10% and 17% lower with the high-carbohydrate and high-MUFA diets, respectively, whereas no change was observed with the high-SFA diet (P < 0.001 for effect of diet). HDL was transiently reduced on the high-carbohydrate diet at weeks 1, 4, and 8, whereas higher fat consumption maintained these levels. The total cholesterol:HDL ratio, although significantly reduced on the high-MUFA diet (P < 0.01), was not different from the other two diets after adjustment for baseline differences. CONCLUSIONS: Energy restriction, independent of diet composition, improves glycemic control; however, reducing SFA intake by replacing SFA with carbohydrate or MUFA reduces LDL maximally during weight loss and to a greater degree than has been shown in weight-stable studies.

Publication Types:


PMID: 10372237 [PubMed - indexed for MEDLINE]

 
19: Nurs Clin North Am. 1993 Mar;28(1):97-112. Related Articles, Links

Nutritional management of diabetes.

Thom SL.

Diabetes Associates, Cleveland, OH 44101-0092.

The ideal therapeutic diet for diabetes mellitus is currently unknown; however, it continues as a cornerstone of treatment for this complex disease. Dietary guidelines dictate a prudent, healthy diet that is recommended for all healthy people, with or without diabetes. Individuals with diabetes are counseled according to their life-style demands and presence of complications. In fact, there may be as many diets for diabetes as people with diabetes, based on the many manifestations, presentations, and complications of diabetes mellitus. Nutrition research in diabetes is a viable pursuit and will continue to generate interest and further modifications until the cure for diabetes is found.

Publication Types:


PMID: 8451221 [PubMed - indexed for MEDLINE]

 
20: J Am Coll Nutr. 2004 Oct;23(5):373-85. Related Articles, Links
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The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review.

Halton TL, Hu FB.

Dept. of Nutrition, Harvard School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA. frank.hu@channing.harvard.edu

For years, proponents of some fad diets have claimed that higher amounts of protein facilitate weight loss. Only in recent years have studies begun to examine the effects of high protein diets on energy expenditure, subsequent energy intake and weight loss as compared to lower protein diets. In this study, we conducted a systematic review of randomized investigations on the effects of high protein diets on dietary thermogenesis, satiety, body weight and fat loss. There is convincing evidence that a higher protein intake increases thermogenesis and satiety compared to diets of lower protein content. The weight of evidence also suggests that high protein meals lead to a reduced subsequent energy intake. Some evidence suggests that diets higher in protein result in an increased weight loss and fat loss as compared to diets lower in protein, but findings have not been consistent. In dietary practice, it may be beneficial to partially replace refined carbohydrate with protein sources that are low in saturated fat. Although recent evidence supports potential benefit, rigorous longer-term studies are needed to investigate the effects of high protein diets on weight loss and weight maintenance.

Publication Types:


PMID: 15466943 [PubMed - indexed for MEDLINE]