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 Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial A high-protein low-fat diet is more effective in improving blood pressure and triglycerides in calorie-restricted obese individuals with newly diagnosed type 2 diabetes Effects of Weight Loss and Long-Term Weight Maintenance With Diets Varying in Protein and Glycemic Index on Cardiovascular Risk Factors: The Diet, Obesity, and Genes (DiOGenes) Study A Randomized, Controlled Trial Effects of High-Protein Versus High-Carbohydrate Diets on Markers of β-Cell Function, Oxidative Stress, Lipid Peroxidation, Proinflammatory Cytokines, and Adipokines in Obese, Premenopausal Women Without Diabetes Long-term effects of a high-protein, low-carbohydrate diet on weight control and cardiovascular risk markers in obese hyperinsulinemic subjects An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes. Short-term effects of substituting protein for carbohydrate in the diets of moderately hypercholesterolemic human subjects. Reduced Body Weight and Adiposity With a High-Protein Diet Improves Functional Status, Lipid Profiles, Glycemic Control, and Quality of Life in Patients With Heart Failure: A Feasibility Study Dietary protein and exercise have additive effects on body composition during weight loss in adult women. The effect of high-protein, low-carbohydrate diets in the treatment of type 2 diabetes: a 12 month randomised controlled trial A controlled trial of protein enrichment of meal replacements for weight reduction with retention of lean body mass Effect of a High Protein Weight Loss Diet on Weight, High-Sensitivity C-Reactive Protein, and Cardiovascular Risk among Overweight and Obese Women: A Parallel Clinical Trial A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults. High-protein, low-fat diets are effective for weight loss and favorably alter biomarkers in healthy adults. Pro-HEART - a randomized clinical trial to test the effectiveness of a high protein diet targeting obese individuals with heart failure: rationale, design and baseline characteristics. High protein intake sustains weight maintenance after body weight loss in humans
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 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 Background / Objectives : There is controversy over dietary protein 's effects on cardiovascular disease risk factors in diabetic subjects . It is unclear whether observed effects are due to increased protein or reduced carbohydrate content of the consumed diets . The aim of this study was to compare the effects of two diets differing in protein to fat ratios on cardiovascular disease risk factors . Subjects/ Methods : A total of 17 obese ( body mass index ( BMI ) ranging from 31 to 45 kg/m2 ) volunteers with type 2 diabetes ( DM2 ) , aged 46±3 years , consumed two diets , each for 4 weeks , with 3 weeks of washout period in a r and om , blind , crossover design . The diets were : ( 1 ) a high-protein low-fat diet ( HP – LF , with 30 % protein , 50 % carbohydrates and 20 % fat ) and ( 2 ) a low-protein high-fat diet ( LP – HF , with 15 % protein , 50 % carbohydrates and 35 % fat ) . Their effects on fasting glycemic control , lipid levels and blood pressure , and on postpr and ial glucose and insulin responses after a st and ard test meal at the beginning and end of each dietary intervention were analyzed . Results : Both diets were equally effective in promoting weight loss and fat loss and in improving fasting glycemic control , total cholesterol and low-density lipoprotein ( LDL ) cholesterol , but the HP – LF diet decreased to a greater extent triglyceride ( TG ) levels ( P=0.04 ) when compared with the LP – HF diet . HP – LF diet improved significantly both systolic and diastolic blood pressure when compared with the LP – HF diet ( P<0.001 and P<0.001 , respectively ) . No differences were observed in postpr and ial glucose and insulin responses . Conclusions : A protein to fat ratio of 1.5 in diets significantly improves blood pressure and TG concentrations in obese individuals with DM2 Background — We sought to separately examine the effects of either weight loss or diets varying in protein content and glycemic index without further changes in body weight on cardiovascular risk factors within the Diet , Obesity , and Genes study ( DiOGenes ) . Methods and Results — DiOGenes is a pan-European controlled dietary intervention study in 932 overweight adults who first lost body weight on an 8-week low-calorie diet and were then r and omized to 1 of 5 ad libitum diets for 26 weeks .  The diets were either high or low protein or high or low glycemic index in 4 combinations or control . Weight loss ( −11.23 kg ; 95 % confidence interval , −11.54 to −10.92 ; P<0.001 ) reduced high-sensitivity C-reactive protein ( −1.15 mg/L ; 95 % confidence interval , −1.30 to −0.41 ; P<0.001 ) , low- and high-density lipoprotein cholesterol , triglycerides , and blood pressure . During the 26-week weight maintenance period in the intention-to-treat analysis , the further decrease of high-sensitivity C-reactive protein blood levels was −0.46 mg/L greater ( 95 % confidence interval , −0.79 to −0.13 ) in the groups assigned to low-glycemic-index diets than in those on high-glycemic-index diets ( P<0.001 ) . Groups on low-protein diets achieved a −0.25 mg/L greater reduction in high-sensitivity C-reactive protein ( 95 % confidence interval , −0.59 to −0.17 ) than those on high-protein diets ( P<0.001 ) , whereas lipid profiles and blood pressure were not differently affected . Conclusions — This large-scale intervention study clearly separates weight loss from dietary composition – related effects . Low-glycemic-index carbohydrates and , to a lesser extent , low-protein intake may specifically reduce low- grade inflammation and associated comorbidities in overweight/obese adults . Clinical Trial Registration — http://www . clinical trials.gov . Unique identifier : NCT00390637 OBJECTIVE To study the effects of high-protein versus high-carbohydrate diets on various metabolic end points ( glucoregulation , oxidative stress [ dichlorofluorescein ] , lipid peroxidation [ malondialdehyde ] , proinflammatory cytokines [ tumor necrosis factor-α and interleukin-6 ] , adipokines , and resting energy expenditure [ REE ] ) with high protein – low carbohydrate ( HP ) and high carbohydrate – low protein ( HC ) diets at baseline and after 6 months of dietary intervention . RESEARCH DESIGN AND METHODS We recruited obese , premenopausal women aged 20–50 years with no diabetes or prediabetes who were r and omized to HC ( 55 % carbohydrates , 30 % fat , and 15 % protein ) or HP ( 40 % carbohydrates , 30 % fat , and 30 % protein ) diets for 6 months . The diets were provided in prepackaged food , which provided 500 kcal restrictions per day . The above metabolic end points were measured with HP and HC diet at baseline and after 6 months of dietary intervention . RESULTS After 6 months of the HP versus HC diet ( 12 in each group ) , the following changes were significantly different by Wilcoxon rank sum test for the following parameters : dichlorofluorescein ( −0.8 vs. −0.3 µmol/L , P < 0.0001 ) , malondialdehyde ( −0.4 vs. −0.2 μmol/L , P = 0.0004 ) , C-reactive protein ( −2.1 vs. −0.8 mg/L , P = 0.0003 ) , E-selectin ( −8.6 vs. −3.7 ng/mL , P = 0.0007 ) , adiponectin ( 1,284 vs. 504 ng/mL , P = 0.0011 ) , tumor necrosis factor-α ( −1.8 vs. −0.9 pg/mL , P < 0.0001 ) , IL-6 ( −1.3 vs. −0.4 pg/mL , P < 0.0001 ) , free fatty acid ( −0.12 vs. 0.16 mmol/L , P = 0.0002 ) , REE ( 259 vs. 26 kcal , P < 0.0001 ) , insulin sensitivity ( 4 vs. 0.9 , P < 0.0001 ) , and β-cell function ( 7.4 vs. 2.1 , P < 0.0001 ) . CONCLUSIONS To our knowledge , this is the first report on the significant advantages of a 6-month hypocaloric HP diet versus hypocaloric HC diet on markers of β-cell function , oxidative stress , lipid peroxidation , proinflammatory cytokines , and adipokines in normal , obese females without diabetes 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 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 result ing 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 result ed 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 postpr and ially 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 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 : The effectiveness of high-protein ( HP ) diets in reducing body weight and adiposity and potentially improving clinical outcomes in heart failure ( HF ) is not known . Objective : This feasibility study was conducted to evaluate the impact of 3 dietary interventions on body weight and adiposity , functional status , lipid profiles , glycemic control , and quality of life ( QOL ) in overweight and obese patients with HF and type 2 diabetes mellitus . Design : Fourteen patients with HF with a body mass index greater than 27 kg/m2 were r and omized to an HP diet , a st and ard protein diet , or a conventional diet . Data were obtained at baseline and 12 weeks . Results : There were no significant differences in age ( 59 ± 10 years ) , sex ( 78 % male ) , New York Heart Association class ( 43 % class II , 57 % class III ) , and HF etiology or left ventricular ejection fraction ( 26 ± 7 ) between the groups at baseline . Patients on the HP diet demonstrated significantly greater reductions in weight ( P = .005 ) , percent body fat ( P = .036 ) , total cholesterol ( P = .016 ) , triglyceride concentrations ( P = .034 ) , and low-density lipoprotein cholesterol ( P = .041 ) and greater improvements in functional status ( 6-minute walk [ P = .010 ] and VO2 peak [ P = .003 ] ) , high-density lipoprotein cholesterol ( P = .006 ) , and physical QOL scores ( P = .022 ) compared with those on st and ard protein and conventional diets . Conclusion : A 12-week HP diet result ed in moderate weight loss and reduced adiposity in a small sample of overweight and obese patients with HF that were associated with improvements in functional status , lipid profiles , glycemic control , and QOL . However , these preliminary findings must be confirmed in studies with more participants and long-term follow-up This study examined the interaction of 2 diets ( high protein , reduced carbohydrates vs. low protein , high carbohydrates ) with exercise on body composition and blood lipids in women ( n = 48 , approximately 46 y old , BMI = 33 kg/m(2 ) ) during weight loss . The study was a 4-mo weight loss trial using a 2 x 2 block design ( Diet x Exercise ) . Diets were equal in total energy ( 7.1 MJ/d ) and lipids ( approximately 30 % energy intake ) but differed in protein content and the ratio of carbohydrate : protein at 1.6 g/(kg . d ) and < 1.5 ( PRO group ) vs. 0.8 g/(kg . d ) and > 3.5 ( CHO group ) , respectively . Exercise comparisons were lifestyle activity ( control ) vs. a supervised exercise program ( EX : 5 d/wk walking and 2 d/wk resistance training ) . Subjects in the PRO and PRO + EX groups lost more total weight and fat mass and tended to lose less lean mass ( P = 0.10 ) than the CHO and CHO + EX groups . Exercise increased loss of body fat and preserved lean mass . The combined effects of diet and exercise were additive for improving body composition . Serum lipid profiles improved in all groups , but changes varied among diet treatments . Subjects in the CHO groups had larger reductions in total cholesterol and LDL cholesterol , whereas subjects in the PRO groups had greater reductions in triacylglycerol and maintained higher concentrations of HDL cholesterol . This study demonstrated that a diet with higher protein and reduced carbohydrates combined with exercise additively improved body composition during weight loss , whereas the effects on blood lipids differed between diet treatments 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 Background While high protein diets have been shown to improve satiety and retention of lean body mass ( LBM ) , this study was design ed to determine effects of a protein-enriched meal replacement ( MR ) on weight loss and LBM retention by comparison to an isocaloric carbohydrate-enriched MR within customized diet plans utilizing MR to achieve high protein or st and ard protein intakes . Methods Single blind , placebo-controlled , r and omized outpatient weight loss trial in 100 obese men and women comparing two isocaloric meal plans utilizing a st and ard MR to which was added supplementary protein or carbohydrate powder . MR was used twice daily ( one meal , one snack ) . One additional meal was included in the meal plan design ed to achieve individualized protein intakes of either 1 ) 2.2 g protein/kg of LBM per day [ high protein diet ( HP ) ] or 2 ) 1.1 g protein/kg LBM/day st and ard protein diet ( SP ) . LBM was determined using bioelectrical impedance analysis ( BIA ) . Body weight , body composition , and lipid profiles were measured at baseline and 12 weeks . Results Eighty-five subjects completed the study . Both HP and SP MR were well tolerated , with no adverse effects . There were no differences in weight loss at 12 weeks ( -4.19 ± 0.5 kg for HP group and -3.72 ± 0.7 kg for SP group , p > 0.1 ) . Subjects in the HP group lost significantly more fat weight than the SP group ( HP = -1.65 ± 0.63 kg ; SP = -0.64 ± 0.79 kg , P = 0.05 ) as estimated by BIA . There were no significant differences in lipids nor fasting blood glucose between groups , but within the HP group a significant decrease in cholesterol and LDL cholesterol was noted at 12 weeks . This was not seen in the SP group . Conclusion Higher protein MR within a higher protein diet result ed in similar overall weight loss as the st and ard protein MR plan over 12 weeks . However , there was significantly more fat loss in the HP group but no significant difference in lean body mass . In this trial , subject compliance with both the st and ard and protein-enriched MR strategy for weight loss may have obscured any effect of increased protein on weight loss demonstrated in prior weight loss studies using whole food diets Studies regarding the effects of high protein ( HP ) diets on cardiovascular ( CVD ) risk factors have reported contradictory results . We aim ed to determine the effects of an HP diet on CVD risk factors and high-sensitivity C-reactive protein ( hs-CRP ) among overweight and obese women . In this r and omized controlled trial , we recruited 60 overweight and obese women , aged 20–65 , into an HP or energy-restricted control diet for three months ( protein , carbohydrate , and fat : 25 % , 45 % , and 30 % versus 15 % , 55 % , and 30 % , resp . ) . Total protein was divided between animal and plant sources in a 1 : 1 ratio , and animal sources were distributed equally between meats and dairy products . Fasting blood sample s , hs-CRP , lipid profile , systolic and diastolic blood pressure , and anthropometric measurements were assessed using st and ard guidelines . Percent change was significantly different between the two diet groups for weight ( st and ard protein ( SP ) : −3.90 ± 0.26 versus HP : −6.10 ± 0.34 % ; P < 0.0001 , resp . ) and waist circumference ( SP : −3.03 ± 0.21 versus HP : −5.06 ± 0.28 % ; P < 0.0001 , resp . ) . Percent change of fasting blood glucose ( FBG ) substantially decreased in the control group compared to the HP group ( −9.13 ± 0.67 versus −4.93 ± 1.4 % ; P = 0.01 , resp . ) . Total cholesterol , systolic blood pressure ( SBP ) , and diastolic blood pressure ( DBP ) decreased both in the HP and in the control diet groups ( P = 0.06 , P = 0.07 , and P = 0.09 , resp . ) ; however , the results were marginally significant . Serum levels of hs-CRP were reduced both in the control ( −0.08 ± 0.11 % , P = 0.06 ) and in the high protein groups ( −0.04 ± 0.09 % , P = 0.06 ) . The energy-restricted HP diet result ed in more beneficial effects on weight loss and reduction of waist circumference . CVD risk factors may improve with HP diets among overweight and obese women . When using isoenergetic weight loss diets , total cholesterol , hs-CRP , and SBP were marginally significantly reduced , independent of dietary protein content . This trial is registered with Clinical Trials.gov NCT01763528 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 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 r and omly 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 There is ample research to support the potential benefits of a high protein diet on clinical outcomes in overweight/obese , diabetic subjects . However , nutritional management of overweight/obese individuals with heart failure ( HF ) and type 2 diabetes mellitus ( DM ) or metabolic syndrome ( MS ) is poorly understood and few clinical guidelines related to nutritional approaches exist for this subgroup . This article describes the design , methods , and baseline characteristics of study participants enrolled in Pro-HEART , a r and omized clinical trial to determine the short term and long term effects of a high protein diet ( 30 % protein [ ~110 g/day ] , 40 % carbohydrates [ 150 g/day ] , 30 % fat [ ~50 g/day ] ) versus a st and ard protein diet ( 15 % protein [ ~55 g/day ] , 55 % carbohydrates [ ~200 g/day ] , 30 % fat [ ~50 g/day ] ) on body weight and adiposity , cardiac structure and function , functional status , lipid profile , glycemic control , and quality of life . Between August , 2009 and May , 2013 , 61 individuals agreed to participate in the study ; 52 ( 85 % ) - mean age 58.2 ± 9.8 years ; 15.4 % Blacks ; 57.7 % Whites ; 19.2 % Hispanics ; 7.7 % Asians ; 73.1 % male ; weight 112.0 ± 22.6 kg - were r and omized to a 3-month intensive weight management program of either a high protein or st and ard protein diet ; data were collected at baseline , 3 months , and 15 months . This study has the potential to reveal significant details about the role of macronutrients in weight management of overweight/obese individuals with HF and DM or MS BACKGROUND : A relatively high percentage of energy intake as protein has been shown to increase satiety and decrease energy efficiency during overfeeding . AIM : To investigate whether addition of protein may improve weight maintenance by preventing or limiting weight regain after weight loss of 5–10 % in moderately obese subjects . DESIGN OF THE STUDY : In a r and omized parallel design , 148 male and female subjects ( age 44.2±10.1 y ; body mass index ( BMI ) 29.5±2.5 kg/m2 ; body fat 37.2±5.0 % ) followed a very low-energy diet ( 2.1 MJ/day ) during 4 weeks . For subsequent 3 months weight-maintenance assessment , they were stratified according to age , BMI , body weight , restrained eating , and resting energy expenditure ( REE ) , and r and omized over two groups . Both groups visited the University with the same frequency , receiving the same counseling on dem and by the dietitian . One group ( n=73 ) received 48.2 g/day additional protein to their diet . Measurements at baseline , after weight loss , and after 3 months weight maintenance were body weight , body composition , metabolic measurements , appetite profile , eating attitude , and relevant blood parameters . RESULTS : Changes in body mass , waist circumference , REE , respiratory quotient ( RQ ) , total energy expenditure ( TEE ) , dietary restraint , fasting blood-glucose , insulin , triacylglycerol , leptin , β-hydroxybutyrate , glycerol , and free fatty acids were significant during weight loss and did not differ between groups . During weight maintenance , the ‘ additional-protein group ’ showed in comparison to the nonadditional-protein group 18 vs 15 en% protein intake , a 50 % lower body weight regain only consisting of fat-free mass , a 50 % decreased energy efficiency , increased satiety while energy intake did not differ , and a lower increase in triacylglycerol and in leptin ; REE , RQ , TEE , and increases in other blood parameters measured did not differ . CONCLUSION : A 20 % higher protein intake , that is , 18 % of energy vs 15 % of energy during weight maintenance after weight loss , result ed in a 50 % lower body weight regain , only consisting of fat-free mass , and related to increased satiety and decreased energy efficiency
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 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 .