title: Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. The Diabetes Excess Weight Loss (DEWL) Trial: a randomised controlled trial of high-protein versus high-carbohydrate diets over 2 years in type 2 diabetes A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women. Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. Randomized trial on protein vs carbohydrate in ad libitum fat reduced diet for the treatment of obesity The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials Long-term effects of a high-protein, low-carbohydrate diet on weight control and cardiovascular risk markers in obese hyperinsulinemic subjects Long-term effects of popular dietary approaches on weight loss and features of insulin resistance Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial. A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults. Effects of weight loss on a low-carbohydrate diet on flow-mediated dilatation, adhesion molecules and adiponectin. Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial 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 The effect of high-protein, low-carbohydrate diets in the treatment of type 2 diabetes: a 12 month randomised controlled trial Low carbohydrate-high protein diet and mortality in a cohort of Swedish women. One-year weight maintenance after significant weight loss in healthy overweight and obese subjects: does diet composition matter? Low-carbohydrate–high-protein diet and long-term survival in a general population cohort Comparative effects of low-carbohydrate high-protein versus low-fat diets on the kidney. Short-term effects of substituting protein for carbohydrate in the diets of moderately hypercholesterolemic human subjects. Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality
abstract: CONTEXT Popular diets , particularly those low in carbohydrates , have challenged current recommendations advising a low-fat , high-carbohydrate diet for weight loss . Potential benefits and risks have not been tested adequately . OBJECTIVE To compare 4 weight-loss diets representing a spectrum of low to high carbohydrate intake for effects on weight loss and related metabolic variables . DESIGN , SETTING , AND PARTICIPANTS Twelve-month r and omized trial conducted in the United States from February 2003 to October 2005 among 311 free-living , overweight/obese ( body mass index , 27 - 40 ) nondiabetic , premenopausal women . INTERVENTION Participants were r and omly assigned to follow the Atkins ( n = 77 ) , Zone ( n = 79 ) , LEARN ( n = 79 ) , or Ornish ( n = 76 ) diets and received weekly instruction for 2 months , then an additional 10-month follow-up . MAIN OUTCOME MEASURES Weight loss at 12 months was the primary outcome . Secondary outcomes included lipid profile ( low-density lipoprotein , high-density lipoprotein , and non-high-density lipoprotein cholesterol , and triglyceride levels ) , percentage of body fat , waist-hip ratio , fasting insulin and glucose levels , and blood pressure . Outcomes were assessed at months 0 , 2 , 6 , and 12 . The Tukey studentized range test was used to adjust for multiple testing . RESULTS Weight loss was greater for women in the Atkins diet group compared with the other diet groups at 12 months , and mean 12-month weight loss was significantly different between the Atkins and Zone diets ( P<.05 ) . Mean 12-month weight loss was as follows : Atkins , -4.7 kg ( 95 % confidence interval [ CI ] , -6.3 to -3.1 kg ) , Zone , -1.6 kg ( 95 % CI , -2.8 to -0.4 kg ) , LEARN , -2.6 kg ( -3.8 to -1.3 kg ) , and Ornish , -2.2 kg ( -3.6 to -0.8 kg ) . Weight loss was not statistically different among the Zone , LEARN , and Ornish groups . At 12 months , secondary outcomes for the Atkins group were comparable with or more favorable than the other diet groups . CONCLUSIONS In this study , premenopausal overweight and obese women assigned to follow the Atkins diet , which had the lowest carbohydrate intake , lost more weight at 12 months than women assigned to follow the Zone diet , and had experienced comparable or more favorable metabolic effects than those assigned to the Zone , Ornish , or LEARN diets [ corrected ] While questions remain about long-term effects and mechanisms , a low-carbohydrate , high-protein , high-fat diet may be considered a feasible alternative recommendation for weight loss . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00079573 Aims /hypothesisTo compare the effectiveness of low-fat high-protein and low-fat high-carbohydrate dietary advice on weight loss , using group-based interventions , among overweight people with type 2 diabetes . Study design Multicentre parallel ( 1:1 ) design , blinded r and omised controlled trial . Methods Individuals with type 2 diabetes aged 30–75 years and a BMI > 27 kg/m2 were r and omised , by an independent statistician using sequentially numbered sealed envelopes , to be prescribed either a low-fat high-protein ( 30 % of energy as protein , 40 % as carbohydrate , 30 % as fat ) or a low-fat high-carbohydrate ( 15 % of energy as protein , 55 % as carbohydrate , 30 % as fat ) diet . Participants attended 18 group sessions over 12 months . Primary outcomes were change in weight and waist circumference assessed at baseline , 6 and 12 months . Secondary outcomes were body fatness , glycaemic control , lipid profile , blood pressure and renal function . A further assessment was undertaken 12 months after the intervention . Research assessors remained blinded to group allocation throughout . Intention-to-treat analysis was performed . Results A total of 419 participants were enrolled ( mean ± SD age 58 ± 9.5 years , BMI 36.6 ± 6.5 kg/m2 and HbA1c 8.1 ± 1.2 % ( 65 mmol/mol ) ) . The study was completed by 70 % ( 294/419 ) . No differences between groups were found in change in weight or waist circumference during the intervention phase or the 12-month follow-up . Both groups had lost weight ( 2–3 kg , p < 0.001 ) and reduced their waist circumference ( 2–3 cm , p < 0.001 ) by 12 months and largely maintained this weight loss for the following 12 months . By 6 months , the difference in self-reported dietary protein between groups was small ( 1.1 % total energy ; p < 0.001 ) . No significant differences between groups were found in secondary outcomes : body fatness , HbA1c , lipids , blood pressure and renal function . There were no important adverse effects . Conclusions /interpretationIn a ‘ real-world ’ setting , prescription of an energy-reduced low-fat diet , with either increased protein or carbohydrate , results in similar modest losses in weight and waist circumference over 2 years . Trial registration : Australia New Zeal and Clinical Trials Register ACTRN12606000490572 Funding : The Health Research Council of New Zeal and ( 06/337 ) Cl aims about the merits or risks of carbohydrate ( CHO ) vs. protein for weight loss diets are extensive , yet the ideal ratio of dietary carbohydrate to protein for adult health and weight management remains unknown . This study examined the efficacy of two weight loss diets with modified CHO/protein ratios to change body composition and blood lipids in adult women . Women ( n = 24 ; 45 to 56 y old ) with body mass indices > 26 kg/m(2 ) were assigned to either a CHO Group consuming a diet with a CHO/protein ratio of 3.5 ( 68 g protein/d ) or a Protein Group with a ratio of 1.4 ( 125 g protein/d ) . Diets were isoenergetic , providing 7100 kJ/d , and similar amounts of fat ( approximately 50 g/d ) . After consuming the diets for 10 wk , the CHO Group lost 6.96 + /- 1.36 kg body weight and the Protein Group lost 7.53 + /- 1.44 kg . Weight loss in the Protein Group was partitioned to a significantly higher loss of fat/lean ( 6.3 + /- 1.2 g/g ) compared with the CHO Group ( 3.8 + /- 0.9 ) . Both groups had significant reductions in serum cholesterol ( approximately 10 % ) , whereas the Protein Group also had significant reductions in triacylglycerols ( TAG ) ( 21 % ) and the ratio of TAG/HDL cholesterol ( 23 % ) . Women in the CHO Group had higher insulin responses to meals and postpr and ial hypoglycemia , whereas women in the Protein Group reported greater satiety . This study demonstrates that increasing the proportion of protein to carbohydrate in the diet of adult women has positive effects on body composition , blood lipids , glucose homeostasis and satiety during weight loss BACKGROUND It is not clear whether varying the protein-to-carbohydrate ratio of weight-loss diets benefits body composition or metabolism . OBJECTIVE The objective was to compare the effects of 2 weight-loss diets differing in protein-to-carbohydrate ratio on body composition , glucose and lipid metabolism , and markers of bone turnover . DESIGN A parallel design included either a high-protein diet of meat , poultry , and dairy foods ( HP diet : 27 % of energy as protein , 44 % as carbohydrate , and 29 % as fat ) or a st and ard-protein diet low in those foods ( SP diet : 16 % of energy as protein , 57 % as carbohydrate , and 27 % as fat ) during 12 wk of energy restriction ( 6 - 6.3 MJ/d ) and 4 wk of energy balance ( approximately 8.2 MJ/d ) . Fifty-seven overweight volunteers with fasting insulin concentrations > 12 mU/L completed the study . RESULTS Weight loss ( 7.9 + /- 0.5 kg ) and total fat loss ( 6.9 + /- 0.4 kg ) did not differ between diet groups . In women , total lean mass was significantly ( P = 0.02 ) better preserved with the HP diet ( -0.1 + /- 0.3 kg ) than with the SP diet ( -1.5 + /- 0.3 kg ) . Those fed the HP diet had significantly ( P < 0.03 ) less glycemic response at weeks 0 and 16 than did those fed the SP diet . After weight loss , the glycemic response decreased significantly ( P < 0.05 ) more in the HP diet group . The reduction in serum triacylglycerol concentrations was significantly ( P < 0.05 ) greater in the HP diet group ( 23 % ) than in the SP diet group ( 10 % ) . Markers of bone turnover , calcium excretion , and systolic blood pressure were unchanged . CONCLUSION Replacing carbohydrate with protein from meat , poultry , and dairy foods has beneficial metabolic effects and no adverse effects on markers of bone turnover or calcium excretion BACKGROUND The possible advantage for weight loss of a diet that emphasizes protein , fat , or carbohydrates has not been established , and there are few studies that extend beyond 1 year . METHODS We r and omly assigned 811 overweight adults to one of four diets ; the targeted percentages of energy derived from fat , protein , and carbohydrates in the four diets were 20 , 15 , and 65 % ; 20 , 25 , and 55 % ; 40 , 15 , and 45 % ; and 40 , 25 , and 35 % . The diets consisted of similar foods and met guidelines for cardiovascular health . The participants were offered group and individual instructional sessions for 2 years . The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content . RESULTS At 6 months , participants assigned to each diet had lost an average of 6 kg , which represented 7 % of their initial weight ; they began to regain weight after 12 months . By 2 years , weight loss remained similar in those who were assigned to a diet with 15 % protein and those assigned to a diet with 25 % protein ( 3.0 and 3.6 kg , respectively ) ; in those assigned to a diet with 20 % fat and those assigned to a diet with 40 % fat ( 3.3 kg for both groups ) ; and in those assigned to a diet with 65 % carbohydrates and those assigned to a diet with 35 % carbohydrates ( 2.9 and 3.4 kg , respectively ) ( P>0.20 for all comparisons ) . Among the 80 % of participants who completed the trial , the average weight loss was 4 kg ; 14 to 15 % of the participants had a reduction of at least 10 % of their initial body weight . Satiety , hunger , satisfaction with the diet , and attendance at group sessions were similar for all diets ; attendance was strongly associated with weight loss ( 0.2 kg per session attended ) . The diets improved lipid-related risk factors and fasting insulin levels . CONCLUSIONS Reduced-calorie diets result in clinical ly meaningful weight loss regardless of which macronutrients they emphasize . ( Clinical Trials.gov number , NCT00072995 . OBJECTIVE : To study the effect on weight loss in obese subjects by replacement of carbohydrate by protein in ad libitum consumed fat-reduced diets . DESIGN : R and omized dietary intervention study over six months comparing two ad libitum fat reduced diets ( 30 % of total energy ) strictly controlled in composition : High-carbohydrate ( HC , protein 12 % of total energy ) or high-protein ( HP , protein 25 % of total energy ) . SETTING AND PARTICIPANTS : Subjects were 65 healthy , overweight and obese subjects ( 50 women , 15 men , aged 18–55 y ) r and omly assigned to HC ( n=25 ) , HP ( n=25 ) or a control group ( C , n=15 ) . All food was provided by self- selection in a shop at the department , and compliance to the diet composition was evaluated by urinary nitrogen excretion . MAIN OUTCOME MEASURE : Change in body weight , body composition and blood lipids . RESULTS : More than 90 % completed the trial . Weight loss after six months was 5.1 kg in the HC group and 8.9 kg in the HP group ( difference 3.7 kg , 95 % confidence interval (CI)(1.3–6.2 kg ) P<0.001 ) , and fat loss was 4.3 kg and 7.6 kg , respectively ( difference 3.3 kg ( 1.1–5.5 kg ) P<0.0001 ) , whereas no changes occurred in the control group . More subjects lost > 10 kg in the HP group ( 35 % ) than in the HC group ( 9 % ) . The HP diet only decreased fasting plasma triglycerides and free fatty acids significantly . CONCLUSIONS : Replacement of some dietary carbohydrate by protein in an ad libitum fat-reduced diet , improves weight loss and increases the proportion of subjects achieving a clinical ly relevant weight loss . More freedom to choose between protein-rich and complex carbohydrate-rich foods may allow obese subjects to choose more lean meat and dairy products , and hence improve adherence to low-fat diets in weight reduction programs Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more OBJECTIVE : To compare the long-term compliance and effects of two low-fat diets differing in carbohydrate to protein ratio on body composition and biomarkers of cardiovascular disease risk in obese subjects with hyperinsulinemia . DESIGN : Outpatient , parallel , clinical intervention study of two groups of subjects r and omly assigned to either a st and ard protein ( SP ; 15 % protein , 55 % carbohydrate ) or high-protein ( HP ; 30 % protein , 40 % carbohydrate ) diet , during 12 weeks of energy restriction ( ∼6.5 MJ/day ) and 4 weeks of energy balance ( ∼8.3 MJ/day ) . Subsequently , subjects were asked to maintain the same dietary pattern for the succeeding 52 weeks with minimal professional support . SUBJECTS : A total of 58 obese , nondietetic subjects with hyperinsulinemia ( 13 males/45 females , mean age 50.2 y , mean body mass index ( BMI ) 34.0 kg/m2 , mean fasting insulin 17.8 mU/l ) participated in the study .  MEASUREMENTS : Body composition , blood pressure , blood lipids , fasting glucose , insulin , CRP and sICAM-1 were measured at baseline and at weeks 16 and 68 . Urinary urea/creatinine ratio was measured at baseline , week 16 and at 3 monthly intervals thereafter . RESULTS : In total , 43 subjects completed the study with similar dropouts in each group ( P=0.76 ) . At week 68 , there was net weight loss ( SP −2.9±3.6 % , HP −4.1±5.8 % ; P<0.01 ) due entirely to fat loss ( P<0.001 ) with no diet effect . Both diets significantly increased HDL cholesterol concentrations ( P<0.001 ) and decreased fasting insulin , insulin resistance , sICAM-1 and CRP levels ( P<0.05 ) . Protein intake was significantly greater in HP during the initial 16 weeks ( P<0.001 ) , but decreased in HP and increased in SP during 52-week follow-up , with no difference between groups at week 68 , indicating poor long-term dietary adherence behaviour to both dietary patterns . CONCLUSION : Without active ongoing dietary advice , adherence to dietary intervention is poor . Nonetheless , both dietary patterns achieved net weight loss and improvements in cardiovascular risk factors Objective : High-carbohydrate (HC)–high-fibre diets are recommended for weight loss and for treating and preventing diseases such as diabetes and cardiovascular disease . We report a r and omised trial comparing high-fat ( HF ) and high-protein ( HP ) diets with the conventional approach . Research design and methods : A total of 93 overweight insulin-resistant women received advice following r and omisation to HF , HP or HC dietary regimes , to achieve weight loss followed by weight maintenance over 12 months . Weight , body composition and measures of carbohydrate and lipid metabolism were investigated . Results : Retention rates were 93 % for HP and 75 % for HC and HF .  Features of the metabolic syndrome improved in all groups during the first 6 months , to a greater extent on HF and HP than an HC . During the second 6 months the HF group had increases in waist circumference ( mean difference 4.4 cm ( 95 % CI 3.0 , 5.8 ) ) , fat mass ( 2.3 kg ( 1.5 , 3.1 ) ) , triglycerides ( 0.28 mmol/l ( 0.09 , 0.46 ) ) and 2 h glucose ( 0.70 mmol/l ( 0.22 , 1.18 ) ) . Overall there was substantial sustained improvement in waist circumference , triglycerides and insulin in the HP group and sustained but more modest changes on HC .  Dietary compliance at 12 months was poor in all groups . Conclusions : HP and HC approaches appear to be appropriate options for insulin-resistant individuals . When recommending HP diets appropriate composition of dietary fat must be ensured . HC diet recommendations must include advice regarding appropriate high-fibre , low glycaemic index foods BACKGROUND Limited evidence suggests that a higher ratio of protein to carbohydrate during weight loss has metabolic advantages . OBJECTIVE The objective was to evaluate the effects of a diet with a high ratio of protein to carbohydrate during weight loss on body composition , cardiovascular disease risk , nutritional status , and markers of bone turnover and renal function in overweight women . DESIGN The subjects were r and omly assigned to 1 of 2 isocaloric 5600-kJ dietary interventions for 12 wk according to a parallel design : a high-protein ( HP ) or a high-carbohydrate ( HC ) diet . RESULTS One hundred women with a mean ( + /-SD ) body mass index ( in kg/m(2 ) ) of 32 + /- 6 and age of 49 + /- 9 y completed the study .  Weight loss was 7.3 + /- 0.3 kg with both diets . Subjects with high serum triacylglycerol ( > 1.5 mmol/L ) lost more fat mass with the HP than with the HC diet ( x + /- SEM : 6.4 + /- 0.7 and 3.4 + /- 0.7 kg , respectively ; P = 0.035 ) and had a greater decrease in triacylglycerol concentrations with the HP ( -0.59 + /- 0.19 mmol/L ) than with the HC ( -0.03 + /- 0.04 mmol/L ) diet ( P = 0.023 for diet x triacylglycerol interaction ) . Triacylglycerol concentrations decreased more with the HP ( 0.30 + /- 0.10 mmol/L ) than with the HC ( 0.10 + /- 0.06 mmol/L ) diet ( P = 0.007 ) . Fasting LDL-cholesterol , HDL-cholesterol , glucose , insulin , free fatty acid , and C-reactive protein concentrations decreased with weight loss . Serum vitamin B-12 increased 9 % with the HP diet and decreased 13 % with the HC diet ( P < 0.0001 between diets ) . Folate and vitamin B-6 increased with both diets ; homocysteine did not change significantly . Bone turnover markers increased 8 - 12 % and calcium excretion decreased by 0.8 mmol/d ( P < 0.01 ) . Creatinine clearance decreased from 82 + /- 3.3 to 75 + /- 3.0 mL/min ( P = 0.002 ) . CONCLUSION An energy-restricted , high-protein , low-fat diet provides nutritional and metabolic benefits that are equal to and sometimes greater than those observed with a high-carbohydrate diet CONTEXT The scarcity of data addressing the health effects of popular diets is an important public health concern , especially since patients and physicians are interested in using popular diets as individualized eating strategies for disease prevention . OBJECTIVE To assess adherence rates and the effectiveness of 4 popular diets ( Atkins , Zone , Weight Watchers , and Ornish ) for weight loss and cardiac risk factor reduction . DESIGN , SETTING , AND PARTICIPANTS A single-center r and omized trial at an academic medical center in Boston , Mass , of overweight or obese ( body mass index : mean , 35 ; range , 27 - 42 ) adults aged 22 to 72 years with known hypertension , dyslipidemia , or fasting hyperglycemia . Participants were enrolled starting July 18 , 2000 , and r and omized to 4 popular diet groups until January 24 , 2002 . INTERVENTION A total of 160 participants were r and omly assigned to either Atkins ( carbohydrate restriction , n=40 ) , Zone ( macronutrient balance , n=40 ) , Weight Watchers ( calorie restriction , n=40 ) , or Ornish ( fat restriction , n=40 ) diet groups . After 2 months of maximum effort , participants selected their own levels of dietary adherence . MAIN OUTCOME MEASURES One-year changes in baseline weight and cardiac risk factors , and self-selected dietary adherence rates per self-report . RESULTS Assuming no change from baseline for participants who discontinued the study , mean ( SD ) weight loss at 1 year was 2.1 ( 4.8 ) kg for Atkins ( 21 [ 53 % ] of 40 participants completed , P = .009 ) , 3.2 ( 6.0 ) kg for Zone ( 26 [ 65 % ] of 40 completed , P = .002 ) , 3.0 ( 4.9 ) kg for Weight Watchers ( 26 [ 65 % ] of 40 completed , P < .001 ) , and 3.3 ( 7.3 ) kg for Ornish ( 20 [ 50 % ] of 40 completed , P = .007 ) . Greater effects were observed in study completers . Each diet significantly reduced the low-density lipoprotein/high-density lipoprotein ( HDL ) cholesterol ratio by approximately 10 % ( all P<.05 ) , with no significant effects on blood pressure or glucose at 1 year . Amount of weight loss was associated with self-reported dietary adherence level ( r = 0.60 ; P<.001 ) but not with diet type ( r = 0.07 ; P = .40 ) . For each diet , decreasing levels of total/HDL cholesterol , C-reactive protein , and insulin were significantly associated with weight loss ( mean r = 0.36 , 0.37 , and 0.39 , respectively ) with no significant difference between diets ( P = .48 , P = .57 , P = .31 , respectively ) . CONCLUSIONS Each popular diet modestly reduced body weight and several cardiac risk factors at 1 year . Overall dietary adherence rates were low , although increased adherence was associated with greater weight loss and cardiac risk factor reductions for each diet group Diets with increased protein and reduced carbohydrates ( PRO ) are effective for weight loss , but the long-term effect on maintenance is unknown . This study compared changes in body weight and composition and blood lipids after short-term weight loss ( 4 mo ) followed by weight maintenance ( 8 mo ) using moderate PRO or conventional high-carbohydrate ( CHO ) diets .  Participants ( age = 45.4 + /- 1.2 y ; BMI = 32.6 + /- 0.8 kg/m(2 ) ; n = 130 ) were r and omized to 2 energy-restricted diets ( -500 kcal/d or -2093 kJ/d ) : PRO with 1.6 g x kg(-1 ) x d(-1 ) protein and < 170 g/d carbohydrates or CHO with 0.8 g x kg(-1 ) x d(-1 ) protein , > 220 g/d carbohydrates . At 4 mo , the PRO group had lost 22 % more fat mass ( FM ) ( -5.6 + /- 0.4 kg ) than the CHO group ( -4.6 + /- 0.3 kg ) but weight loss did not differ between groups ( -8.2 + /- 0.5 kg vs. -7.0 + /- 0.5 kg ; P = 0.10 ) . At 12 mo , the PRO group had more participants complete the study ( 64 vs. 45 % , P < 0.05 ) with greater improvement in body composition ; however , weight loss did not differ between groups ( -10.4 + /- 1.2 kg vs. -8.4 + /- 0.9 kg ; P = 0.18 ) . Using a compliance criterion of participants attaining > 10 % weight loss , the PRO group had more participants ( 31 vs. 21 % ) lose more weight ( -16.5 + /- 1.5 vs. -12.3 + /- 0.9 kg ; P < 0.01 ) and FM ( -11.7 + /- 1.0 vs. -7.9 + /- 0.7 kg ; P < 0.01 ) than the CHO group . The CHO diet reduced serum cholesterol and LDL cholesterol compared with PRO ( P < 0.01 ) at 4 mo , but the effect did not remain at 12 mo . PRO had sustained favorable effects on serum triacylglycerol ( TAG ) , HDL cholesterol ( HDL-C ) , and TAG : HDL-C compared with CHO at 4 and 12 mo ( P < 0.01 ) . The PRO diet was more effective for FM loss and body composition improvement during initial weight loss and long-term maintenance and produced sustained reductions in TAG and increases in HDL-C compared with the CHO diet Our aim was to determine whether short-term weight loss on a low-carbohydrate/low-saturated fat diet improved endothelial function compared with a conventional high-carbohydrate diet , as this diet is expected to lower both blood glucose and LDL-cholesterol . In a r and omised parallel design of two energy-restricted diets in an outpatient setting , thirty-six subjects ( BMI 33 ( sem 4 ) kg/m2 ) were r and omised to a low- or high-carbohydrate diet both low in saturated fat .  Flow-mediated dilatation ( FMD ) , fasting glucose , insulin , lipids , adiponectin and adhesion molecules were measured at baseline , during weight loss and at 52 weeks . FMD did not change with either diet ( 5.2 ( sem 0.6 ) to 5.5 ( sem 0.6 ) % ) despite weight loss of 5 % and significant reductions in glucose and insulin and LDL-cholesterol and was not different after sustained weight loss of 5 % at 52 weeks . Adiponectin fell by 6 % at 12 weeks ( P = 0.1 ) with weight loss but rose by 17 % at 12 months ( P < 0.05 ) with 5 % weight loss . There were no effects of diet . In contradistinction , adhesion molecules fell at 12 weeks , vascular cell adhesion molecule-1 by 14 % and intracellular adhesion molecule-1 by 13 % ( both P < 0.05 ) . There were correlations between change in adiponectin at 12 months and change in HDL ( r 0.778 , P < 0.01 ) and glucose ( r - 0.563 , P = 0.057 ) . In summary , weight loss does not improve FMD . Novel cardiovascular risk factors improved at 12 weeks but the improvement in adiponectin was delayed BACKGROUND : We have previously reported that a fat-reduced high-protein diet had more favourable effects on body weight loss over 6 months than a medium-protein diet . OBJECTIVE : To extend this observation by a further 6–12 months less stringent intervention and a 24 months follow-up . DESIGN : A r and omised 6 months strictly controlled dietary intervention followed by 6–12 months dietary counselling period , and a subsequent 24 months follow-up , comparing an ad libitum , fat-reduced diet ( 30 % of energy ) either high in protein ( 25 % of energy , HP ) or medium in protein ( 12 % of energy , MP).SUBJECTS : A total of 50 overweight and obese subjects ( age : 19–55 y ; BMI : 26–34 kg/m2 ) . MEASUREMENTS : Change in body weight , body composition and blood parameters . RESULTS : After 6 months , the HP group ( n=23 ) achieved a greater weight loss than the MP group ( n=23 ) ( 9.4 vs 5.9 kg ) ( P<0.01 ) . After 12 months , 8 % had dropped out in the HP vs 28 % in the MP group ( P<0.07 ) . After 12 months , the weight loss was not significantly greater among the subjects in the HP group ( 6.2 and 4.3 kg ) , but they had a 10 % greater reduction in intra-abdominal adipose tissue and more in the HP group ( 17 % ) lost > 10 kg than in the MP ( P<0.09 ) . At 24 months , both groups tended to maintain their 12 months weight loss , but more than 50 % were lost to follow-up . CONCLUSION : A fat-reduced diet high in protein seems to enhance weight loss and provide a better long-term maintenance of reduced intra-abdominal fat stores Aims /hypothesisThis 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 r and omly 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 ( ~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≤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 /interpretationA 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 Aims /hypothesisShort-term dietary studies suggest that high-protein diets can enhance weight loss and improve glycaemic control in people with type 2 diabetes . However , the long-term effects of such diets are unknown . The aim of this study was to determine whether high-protein diets are superior to high-carbohydrate diets for improving glycaemic control in individuals with type 2 diabetes . Methods Overweight/obese individuals ( BMI 27–40 kg/m2 ) with type 2 diabetes ( HbA1c 6.5–10 % ) were recruited for a 12 month , parallel design , dietary intervention trial conducted at a diabetes specialist clinic ( Melbourne , VIC , Australia ) . Of the 108 initially r and omised , 99 received advice  to follow low-fat ( 30 % total energy ) diets that were either high in protein ( 30 % total energy , n = 53 ) or high in carbohydrate ( 55 % total energy , n = 46 ) . Dietary assignment was done by a third party using computer-generated r and om numbers . The primary endpoint was change in HbA1c . Secondary endpoints included changes in weight , lipids , blood pressure , renal function and calcium loss . Study endpoints were assessed blinded to the diet group , but the statistical analysis was performed unblinded . This study used an intention-to-treat model for all participants who received dietary advice . Follow-up visits were encouraged regardless of dietary adherence and last measurements were carried forward for study non-completers . Results Ninety-nine individuals were included in the analysis ( 53 in high protein group , 46 in high carbohydrate group ) . HbA1c decreased in both groups over time , with no significant difference between groups ( mean difference of the change at 12 months ; 0.04 [ 95 % CI −0.37 , 0.46 ] ; p = 0.44 ) . Both groups also demonstrated decreases over time in weight , serum triacylglycerol and total cholesterol , and increases in HDL-cholesterol . No differences in blood pressure , renal function or calcium loss were seen . Conclusions /interpretationThese results suggest that there is no superior long-term metabolic benefit of a high-protein diet over a high-carbohydrate in the management of type 2 diabetes . Trial registration ACTRN12605000063617 ( www.anzctr.org.au ) . Funding This study was funded by a nutritional research grant from Meat and Livestock Australia ( MLA ) . J.E. Shaw is supported by NHMRC Fellowship 586623 OBJECTIVE The long-term health consequences of diets used for weight control are not established . We have evaluated the association of the frequently recommended low carbohydrate diets - usually characterized by concomitant increase in protein intake - with long-term mortality . DESIGN The Women 's Lifestyle and Health cohort study initiated in Sweden during 1991 - 1992 , with a 12-year almost complete follow up . SETTING The Uppsala Health Care Region . SUBJECTS 42,237 women , 30 - 49 years old at baseline , volunteers from a r and om sample , who completed an extensive question naire  and were traced through linkages to national registries until 2003 . MAIN OUTCOME MEASURES We evaluated the association of mortality with : decreasing carbohydrate intake ( in deciles ) ; increasing protein intake ( in deciles ) and an additive combination of these variables ( low carbohydrate-high protein score from 2 to 20 ) , in Cox models controlling for energy intake , saturated fat intake and several nondietary covariates . RESULTS Decreasing carbohydrate or increasing protein intake by one decile were associated with increase in total mortality by 6 % ( 95 % CI : 0 - 12 % ) and 2 % ( 95 % CI : -1 to 5 % ) , respectively . For cardiovascular mortality , amongst women 40 - 49 years old at enrolment , the corresponding increases were , respectively , 13 % ( 95 % CI : -4 to 32 % ) and 16 % ( 95 % CI : 5 - 29 % ) , with the additive score being even more predictive . CONCLUSIONS A diet characterized by low carbohydrate and high protein intake was associated with increased total and particularly cardiovascular mortality  amongst women . Vigilance with respect to long-term adherence to such weight control regimes is advisable BACKGROUND For many people , maintenance of weight loss is elusive . Whereas high-protein ( HP ) diets have been found to be superior to high-carbohydrate ( HC ) diets for weight loss in the short term , their benefits long term are unclear , particularly for weight maintenance . Furthermore , the literature lacks consensus on the long-term effects of an HP diet on cardiovascular disease risk factors . OBJECTIVE The objective was to investigate whether macronutrient dietary composition plays a role in weight maintenance and in improvement of cardiovascular disease risk factors . DESIGN The study comprised 2 phases . Phase 1 featured a very-low-energy diet for 3 mo . In phase 2 , the subjects were r and omly assigned to an HP or an HC diet for 12 mo . The diets were isocaloric , tightly controlled , and individually prescribed for weight maintenance . The subjects were overweight or obese but otherwise healthy men and women . RESULTS The subjects lost an average of 16.5 kg during phase 1 and maintained a mean ( + /-SEM ) weight loss of 14.5 + /- 1.2 kg ( P < 0.001 ) during phase 2 ; no significant differences between groups were observed . By the end of the study , reductions in systolic blood pressure were 14.3 + /- 2.4 mm Hg for the HP group and 7.7 + /- 2.2 mm Hg for the HC group ( P < 0.045 ) . Forty-seven percent of the 180 subjects who began the study completed both phases . CONCLUSIONS The results indicate that the protein or carbohydrate content of the diet has no effect on successful weight-loss maintenance . A general linear model analysis indicated that dietary treatment ( HP or HC ) was a significant factor in systolic blood pressure change and in favor of the HP diet . This trial was registered at www . clinical trials.gov as NCT 00625236 Objective : We have evaluated the effects on mortality of habitual low carbohydrate – high-protein diets that are thought to contribute to weight control . Design : Cohort investigation . Setting : Adult Greek population .Subjects methods : Follow-up was performed from 1993 to 2003 in the context of the Greek component of the European Prospect i ve Investigation into Cancer and nutrition . Participants were 22 944 healthy adults , whose diet was assessed through a vali date d question naire .  Participants were distributed by increasing deciles according to protein intake or carbohydrate intake , as well as by an additive score generated by increasing decile intake of protein and decreasing decile intake of carbohydrates . Proportional hazards regression was used to assess the relation between high protein , high carbohydrate and the low carbohydrate – high protein score on the one h and and mortality on the other . Results : During 113 230 persons years of follow-up , there were 455 deaths . In models with energy adjustment , higher intake of carbohydrates was associated with significant reduction of total mortality , whereas higher intake of protein was associated with nonsignificant increase of total mortality ( per decile , mortality ratios 0.94 with 95 % CI 0.89 –0.99 , and 1.02 with 95 % CI 0.98 –1.07 respectively ) . Even more predictive of higher mortality were high values of the additive low carbohydrate – high protein score ( per 5 units , mortality ratio 1.22 with 95 % CI 1.09 –to 1.36 ) . Positive associations of this score were noted with respect to both cardiovascular and cancer mortality . Conclusion : Prolonged consumption of diets low in carbohydrates and high in protein is associated with an increase in total mortality BACKGROUND AND OBJECTIVES Concerns exist about deleterious renal effects of low-carbohydrate high-protein weight loss diets . This issue was addressed in a secondary analysis of a parallel r and omized , controlled long-term trial . DESIGN , SETTING , PARTICIPANTS , AND MEASUREMENTS Between 2003 and 2007 , 307 obese adults without serious medical illnesses at three United States academic centers were r and omly assigned to a low-carbohydrate high-protein or a low-fat weight-loss diet for 24 months . Main outcomes included renal filtration ( GFR ) indices ( serum creatinine , cystatin C , creatinine clearance ) ; 24-hour urinary volume ; albumin ; calcium excretion ; and serum solutes at 3 , 12 , and 24 months . RESULTS Compared with the low-fat diet , low-carbohydrate high-protein consumption was associated with minor reductions in serum creatinine ( relative difference , -4.2 % ) and cystatin C ( -8.4 % ) at 3 months and relative increases in creatinine clearance at 3 ( 15.8 ml/min ) and 12 ( 20.8 ml/min ) months ; serum urea at 3 ( 14.4 % ) , 12 ( 9.0 % ) , and 24 ( 8.2 % ) months ; and 24-hour urinary volume at 12 ( 438 ml ) and 24 ( 268 ml ) months . Urinary calcium excretion increased at 3 ( 36.1 % ) and 12 ( 35.7 % ) months without changes in bone density or clinical presentations of new kidney stones . CONCLUSIONS In healthy obese individuals , a low-carbohydrate high-protein weight-loss diet over 2 years was not associated with noticeably harmful effects on GFR , albuminuria , or fluid and electrolyte balance compared with a low-fat diet . Further follow-up is needed to determine even longer-term effects on kidney function The short-term effects on plasma lipoprotein lipids of substituting meat and dairy protein for carbohydrate in the diets of 10 free-living moderately hypercholesterolemic human subjects ( four men , six women ) were studied under closely supervised dietary control during the consumption of constant , low intakes of fat and cholesterol and the maintenance of stable body weight as well as constant fiber consumption . Subjects were r and omly allocated to either the high or low protein diets ( mean , 23 % v 11 % of energy as protein , 24 % as fat , and 53 % v 65 % as carbohydrate ) and then switched to the other diet for another 4 to 5 weeks . Mean fasting plasma high-density lipoprotein cholesterol ( HDL-C ) was significantly higher by 12 % + /- 4 % ( 0.97 + /- 0.08 v 0.89 + /- 0.08 mmol/L , P less than .01 ) , whereas mean total cholesterol ( TC ) was lower by 6.5 % + /- 1.3 % ( 5.7 + /- 0.3 v 6.1 + /- 0.3 mmol/L , P less than .001 ) , mean low-density lipoprotein-cholesterol ( LDL-C ) lower by 6.4 % + /- 2.0 % ( 4.5 + /- 0.2 v 4.8 + /- 0.2 mmol/L , P less than .02 ) , mean total triglycerides ( TG ) lower by 23 % + /- 5 % ( 1.7 + /- 0.1 v 2.4 + /- 0.3 mmol/L , P less than .02 ) , and mean high versus low protein diet . Mean values for LDL-C were significantly lower during weeks 3 to 5 of the high protein diet than during either weeks 1 to 5 or weeks 1 to 2 of the high protein diet ( 4.3 + /- 0.3 , 4.5 + /- 0.2 , and 4.7 + /- 0.3 mmol/L , respectively , P less than .05 ) and 11 % + /- 3 % lower than on low protein diet , P less than .005 . The ratio of plasma LDL-C to HDL-C was consistently lower by 17 % + /- 3 % during the high versus low protein diet ( 4.9 + /- 0.5 v 5.8 + /- 0.5 , P less than .001 ) . Lowering plasma TC and LDL-C and total TG and VLDL-TG and increasing HDL-C by chronic isocaloric substitution of dietary for carbohydrate may enhance the cardiovascular risk reduction obtained by restriction of dietary fat and cholesterol BACKGROUND Data on the long-term association between low-carbohydrate diets and mortality are sparse . OBJECTIVE To examine the association of low-carbohydrate diets with mortality during 26 years of follow-up in women and 20 years in men . DESIGN Prospect i ve cohort study of women and men who were followed from 1980 ( women ) or 1986 ( men ) until 2006 .  Low-carbohydrate diets , either animal-based ( emphasizing animal sources of fat and protein ) or vegetable-based ( emphasizing vegetable sources of fat and protein ) , were computed from several vali date d food-frequency question naires assessed during follow-up . SETTING Nurses ' Health Study and Health Professionals ' Follow-up Study . PARTICIPANTS 85 168 women ( aged 34 to 59 years at baseline ) and 44 548 men ( aged 40 to 75 years at baseline ) without heart disease , cancer , or diabetes . MEASUREMENTS Investigators documented 12 555 deaths ( 2458 cardiovascular-related and 5780 cancer-related ) in women and 8678 deaths ( 2746 cardiovascular-related and 2960 cancer-related ) in men . RESULTS The overall low-carbohydrate score was associated with a modest increase in overall mortality in a pooled analysis ( hazard ratio [ HR ] comparing extreme deciles , 1.12 [ 95 % CI , 1.01 to 1.24 ] ; P for trend = 0.136 ) . The animal low-carbohydrate score was associated with higher all-cause mortality ( pooled HR comparing extreme deciles , 1.23 [ CI , 1.11 to 1.37 ] ; P for trend = 0.051 ) , cardiovascular mortality ( corresponding HR , 1.14 [ CI , 1.01 to 1.29 ] ; P for trend = 0.029 ) , and cancer mortality ( corresponding HR , 1.28 [ CI , 1.02 to 1.60 ] ; P for trend = 0.089 ) . In contrast , a higher vegetable low-carbohydrate score was associated with lower all-cause mortality ( HR , 0.80 [ CI , 0.75 to 0.85 ] ; P for trend < /= 0.001 ) and cardiovascular mortality ( HR , 0.77 [ CI , 0.68 to 0.87 ] ; P for trend < 0.001 ) . LIMITATIONS Diet and lifestyle characteristics were assessed with some degree of error . Sensitivity analyses indicated that results were probably not substantively affected by residual confounding or an unmeasured confounder . Participants were not a representative sample of the U.S. population . CONCLUSION A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women , whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates . PRIMARY FUNDING SOURCE National Institutes of Health
target: No significant differences were observed for weight , waist circumference , fat mass , blood lipids ( i.e. total cholesterol , LDL-cholesterol , HDL-cholesterol , triacylglycerols ) , C-reactive protein , diastolic and systolic blood pressure , fasting glucose and glycosylated hemoglobin .
  Sensitivity analysis of high quality RCTs confirmed the data of the primary analyses , while exclusion of studies with diabetic subjects result ed in an additional benefit of high-protein diets with respect to a more marked increase in HDL-cholesterol .
  Conclusion According to the present meta- analysis of long-term RCTs , high-protein diets exerted neither specific beneficial nor detrimental effects on outcome markers of obesity , cardiovascular disease or glycemic control .
background: Background Meta-analyses of short-term studies indicate favorable effects of higher protein vs. lower protein diets on health outcomes like adiposity or cardiovascular risk factors , but their long-term effects are unknown .