title: The effect of protein intake on 24-h energy expenditure during energy restriction. Protein intake, weight loss, and bone mineral density in postmenopausal women. Effects of protein versus simple sugar intake on weight loss in polycystic ovary syndrome (according to the National Institutes of Health criteria). Diets with high or low protein content and glycemic index for weight-loss maintenance. Moderate carbohydrate, moderate protein weight loss diet reduces cardiovascular disease risk compared to high carbohydrate, low protein diet in obese adults: A randomized clinical trial High-protein, low-fat diets are effective for weight loss and favorably alter biomarkers in healthy adults. A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. Dietary protein and exercise have additive effects on body composition 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. Separate effects of reduced carbohydrate intake and weight loss on atherogenic dyslipidemia. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Randomized trial on protein vs carbohydrate in ad libitum fat reduced diet for the treatment of obesity Effect of a high-protein, energy-restricted diet on weight loss and energy expenditure after weight stabilization in hyperinsulinemic subjects 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. A High-Protein Diet With Resistance Exercise Training Improves Weight Loss and Body Composition in Overweight and Obese Patients With Type 2 Diabetes A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults. A controlled trial of protein enrichment of meal replacements for weight reduction with retention of lean body mass Effect of a high-protein, high-monounsaturated fat weight loss diet on glycemic control and lipid levels in type 2 diabetes. High protein vs high carbohydrate hypoenergetic diet for the treatment of obese hyperinsulinemic subjects The role of energy expenditure in the differential weight loss in obese women on low-fat and low-carbohydrate diets. A randomized trial of the effects of two types of short-term hypocaloric diets on weight loss in women with polycystic ovary syndrome. 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 Short-term effects of substituting protein for carbohydrate in the diets of moderately hypercholesterolemic human subjects. Effects of protein vs. carbohydrate-rich diets on fuel utilisation in obese women during weight loss. Effects of an 8-week high-protein or high-carbohydrate diet in adults with hyperinsulinemia.
abstract: OBJECTIVE To investigate whether protein intake influences the decline in energy expenditure during energy restriction . DESIGN Cross-over study of three diets of 4.2 MJ/d for 7 days : one diet with 36 % energy as protein and two with 15 % energy as protein , one high in carbohydrate and the other high in fat . SUBJECTS Two men and six women aged 31 - 57 y. BMI 27.B-34.1 kg/m2 . MEASUREMENTS 24-h energy expenditure ( 24-h EE ) , sleeping metabolic rate ( SMR ) and body weight on days 0 and 7 of each diet ; 24-h urinary nitrogen excretion ( 24-h UN ) on days 0 - 7 of each diet . RESULTS 24-h EE and SMR declined on all three diets but the decrease was significantly less on the high protein diet than on the two low protein diets .  Weight loss was similar on all three diets . 24-h UN was less than N intake on the high protein diet but greater than N intake on the two low protein diets . CONCLUSIONS Maintaining protein intake reduces the decrease in energy expenditure during energy restriction BACKGROUND Higher protein diets are promoted for effective weight loss . Striated tissues in omnivorous diets contain high- quality protein , but limited data exist regarding their effects on bone . METHODS To examine the effects of energy restriction-induced weight loss with higher protein omnivorous diets versus lower protein vegetarian diets on  bone mineral density  in overweight postmenopausal women , two r and omized controlled feeding studies were conducted . In Study 1 , 28 women consumed 750 kcal/day energy deficit diets with 18 % energy from protein via lacto-ovo vegetarian sources ( normal protein , n = 15 ) or 30 % energy from protein with 40 % of protein from lean pork ( higher protein , n = 13 , omnivorous ) for 12 weeks . In Study 2 , 54 women consumed their habitual diet ( control , n = 11 ) or 1,250 kcal/day diets with 16 % energy from nonmeat protein sources ( n = 14 ) or 26 % energy from protein , including chicken ( n = 15 ) or beef ( n = 14 ) for 9 weeks . RESULTS Study 1 : With weight loss ( normal protein -11.2 % , higher protein -10.1 % ) , bone mineral density was not significantly changed in normal protein ( -0.003 ± 0.003 g/cm(2 ) , -0.3 % ) but decreased in higher protein ( -0.0167 ± 0.004 g/cm(2 ) , -1 . 4 % , group-by-time p < .05 ) . Study 2 : The control , nonmeat , chicken , and beef groups lost 1.5 % , 7.7 % , 10.4 % , and 8.1 % weight and 0.0 % , 0.4 % , 1.1 % , and 1.4 % bone mineral density , respectively . The change of bone mineral density was significant for chicken and beef compared with the control ( group-by-time , p < .05 ) . Markers of calcium metabolism and bone homeostasis in blood and urine were not changed over time or differentially affected by diet . CONCLUSION Consumption of higher protein omnivorous diets promoted decreased bone mineral density after weight loss in overweight postmenopausal women OBJECTIVE To compare the effects of protein vs. simple sugars on weight loss , body composition , and metabolic and endocrine parameters in polycystic ovary syndrome ( PCOS ) . DESIGN A 2-month , free-living , r and omized , single-blinded study . SETTING University PCOS clinic . PATIENT(S ) Thirty-three patients with PCOS . INTERVENTION(S ) To achieve a final energy reduction of 450 kcal/day , first the daily energy intake was reduced by 700 kcal ; then a 240-kcal supplement containing either whey protein or simple sugars was added . MAIN OUTCOME MEASURE(S ) Changes in weight , fat mass , fasting glucose and insulin , plasma lipoproteins , and sex steroids . RESULT ( S ) Twenty-four subjects ( 13 in the simple sugars group and 11 in the protein group ) completed the study . The protein group lost more weight ( -3.3 + /- 0.8 kg vs. -1.1 + /- 0.6 kg ) and more fat mass ( -3.1 + /- 0.9 kg vs. -0.5 + /- 0.6 kg ) and had larger decreases in serum cholesterol ( -33.0 + /- 8.4 mg/dL vs. -2.3 + /- 6.8 mg/dL ) , high-density lipoprotein cholesterol ( -4.5 + /- 1.3 mg/dL vs. -0.4 + /- 1.3 mg/dL ) , and apoprotein B ( -20 + /- 5 mg/dL vs. 3 + /- 5 mg/dL ) . CONCLUSION ( S ) In patients with PCOS , a hypocaloric diet supplemented with protein reduced body weight , fat mass , serum cholesterol , and apoprotein B more than the diet supplemented with simple sugars BACKGROUND Studies of weight-control diets that are high in protein or low in glycemic index have reached varied conclusions , probably owing to the fact that the studies had insufficient power . METHODS We enrolled overweight adults from eight European countries who had lost at least 8 % of their initial body weight with a 3.3-MJ ( 800-kcal ) low-calorie diet .  Participants were r and omly assigned , in a two-by-two factorial design , to one of five ad libitum diets to prevent weight regain over a 26-week period : a low-protein and low-glycemic-index diet , a low-protein and high-glycemic-index diet , a high-protein and low-glycemic-index diet , a high-protein and high-glycemic-index diet , or a control diet . RESULTS A total of 1209 adults were screened ( mean age , 41 years ; body-mass index [ the weight in kilograms divided by the square of the height in meters ] , 34 ) , of whom 938 entered the low-calorie-diet phase of the study . A total of 773 participants who completed that phase were r and omly assigned to one of the five maintenance diets ; 548 completed the intervention ( 71 % ) . Fewer participants in the high-protein and the low-glycemic-index groups than in the low-protein-high-glycemic-index group dropped out of the study ( 26.4 % and 25.6 % , respectively , vs. 37.4 % ; P=0.02 and P=0.01 for the respective comparisons ) . The mean initial weight loss with the low-calorie diet was 11.0 kg . In the analysis of participants who completed the study , only the low-protein-high-glycemic-index diet was associated with subsequent significant weight regain ( 1.67 kg ; 95 % confidence interval [ CI ] , 0.48 to 2.87 ) . In an intention-to-treat analysis , the weight regain was 0.93 kg less ( 95 % CI , 0.31 to 1.55 ) in the groups assigned to a high-protein diet than in those assigned to a low-protein diet ( P=0.003 ) and 0.95 kg less ( 95 % CI , 0.33 to 1.57 ) in the groups assigned to a low-glycemic-index diet than in those assigned to a high-glycemic-index diet ( P=0.003 ) . The analysis involving participants who completed the intervention produced similar results . The groups did not differ significantly with respect to diet-related adverse events . CONCLUSIONS In this large European study , a modest increase in protein content and a modest reduction in the glycemic index led to an improvement in study completion and maintenance of weight loss . ( Funded by the European Commission ; Clinical Trials.gov number , NCT00390637 . ) Background To evaluate the metabolic effects of two weight loss diets differing in macronutrient composition on features of dyslipidemia and post-pr and ial insulin ( INS ) response to a meal challenge in overweight/obese individuals . Methods This study was a parallel-arm r and omized 4 mo weight loss trial . Adults ( n = 50 , 47 ± 7 y ) matched on BMI ( 33.6 ± 0.6 kg/m2 , P = 0.79 )  consumed energy restricted diets ( deficit ~500 kcal/d ) : PRO ( 1.6 g.kg-1.d-1 protein and < 170 g/d carbohydrate ) or CHO ( 0.8 g.kg-1.d-1 protein and > 220 g/d carbohydrate ) for 4 mos . Meal challenges of respective diets were utilized for determination of blood lipids and post-pr and ial INS and glucose response at the beginning and end of the study . Results There was a trend for PRO to lose more weight ( -9.1 % vs. -7.3 % , P = 0.07 ) with a significant reduction in percent fat mass compared to CHO ( -8.7 % vs. -5.7 % ; P = 0.03 ) . PRO also favored reductions in triacylglycerol ( -34 % vs. -14 % ; P < 0.05 ) and increases in HDL-C ( + 5 % vs. -3 % ; P = 0.05 ) ; however , CHO favored reduction in LDL-C ( -7 % vs. + 2.5 % ; P < 0.05 ) . INS responses to the meal challenge were improved in PRO compared to CHO ( P < 0.05 ) at both 1 hr ( -34.3 % vs. -1.0 % ) and 2 hr ( -9.2 % vs. + 46.2 % ) , an effect that remained significant after controlling for weight or fat loss ( both P < 0.05 ) . Conclusion A weight loss diet with moderate carbohydrate , moderate protein results in more favorable changes in body composition , dyslipidemia , and post-pr and ial INS response compared to a high carbohydrate , low protein diet suggesting an additional benefit beyond weight management to include augmented risk reduction for metabolic disease 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 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 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 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 Low-carbohydrate diets have been used to manage obesity and its metabolic consequences . OBJECTIVE The objective was to study the effects of moderate carbohydrate restriction on  atherogenic dyslipidemia before and after weight loss and in conjunction with a low or high dietary saturated fat intake . DESIGN After 1 wk of consuming a basal diet , 178 men with a mean body mass index ( in kg/m(2 ) ) of 29.2 + /- 2.0 were r and omly assigned to consume diets with carbohydrate contents of 54 % ( basal diet ) , 39 % , or 26 % of energy and with a low saturated fat content ( 7 - 9 % of energy ) ; a fourth group consumed a diet with 26 % of energy as carbohydrate and 15 % as saturated fat . After 3 wk , the mean weight loss ( 5.12 + /- 1.83 kg ) was induced in all diet groups by a reduction of approximately 1000 kcal/d for 5 wk followed by 4 wk of weight stabilization . RESULTS The 26%-carbohydrate , low-saturated-fat diet reduced triacylglycerol , apolipoprotein B , small LDL mass , and total : HDL cholesterol and increased LDL peak diameter . These changes were significantly different from those with the 54%-carbohydrate diet . After subsequent weight loss , the changes in all these variables were significantly greater and the reduction in LDL cholesterol was significantly greater with the 54%-carbohydrate diet than with the 26%-carbohydrate diet . With the 26%-carbohydrate diet , lipoprotein changes with the higher saturated fat intakes were not significantly different from those with the lower saturated fat intakes , except for LDL cholesterol , which decreased less with the higher saturated fat intake because of an increase in mass of large LDL . CONCLUSIONS Moderate carbohydrate restriction and weight loss provide equivalent but nonadditive approaches to improving atherogenic dyslipidemia . Moreover , beneficial lipid changes result ing from a reduced carbohydrate intake were not significant after weight loss BACKGROUND The anabolic effect of resistance exercise is enhanced by the provision of dietary protein . OBJECTIVES We aim ed to determine the ingested protein dose response of muscle ( MPS ) and albumin protein synthesis ( APS ) after resistance exercise . In addition , we measured the phosphorylation of c and i date signaling proteins thought to regulate acute changes in MPS . DESIGN Six healthy young men reported to the laboratory on 5 separate occasions to perform an intense bout of leg-based resistance exercise . After exercise , participants consumed , in a r and omized order , drinks containing 0 , 5 , 10 , 20 , or 40 g whole egg protein .  Protein synthesis and whole-body leucine oxidation were measured over 4 h after exercise by a primed constant infusion of [1-(13)C]leucine . RESULTS MPS displayed a dose response to dietary protein ingestion and was maximally stimulated at 20 g. The phosphorylation of ribosomal protein S6 kinase ( Thr(389 ) ) , ribosomal protein S6 ( Ser(240/244 ) ) , and the epsilon-subunit of eukaryotic initiation factor 2B ( Ser(539 ) ) were unaffected by protein ingestion . APS increased in a dose-dependent manner and also reached a plateau at 20 g ingested protein . Leucine oxidation was significantly increased after 20 and 40 g protein were ingested . CONCLUSIONS Ingestion of 20 g intact protein is sufficient to maximally stimulate MPS and APS after resistance exercise . Phosphorylation of c and i date signaling proteins was not enhanced with any dose of protein ingested , which suggested that the stimulation of MPS after resistance exercise may be related to amino acid availability . Finally , dietary protein consumed after exercise in excess of the rate at which it can be incorporated into tissue protein stimulates irreversible oxidation 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 OBJECTIVE : To determine the effect of replacing some dietary carbohydrate with protein , during energy restriction , on weight loss , total energy expenditure ( TEE ) , resting energy expenditure ( REE ) , respiratory quotient ( RQ ) , and the thermic effect of feeding ( TEF ) in subjects with hyperinsulinemia . DESIGN : Parallel , clinical intervention study of 12 weeks energy restriction ( 6.5 MJ/day ) and 4 weeks energy balance ( 8.2 MJ/day ) in two groups of subjects r and omly assigned to either a high-protein ( HP ) diet ( 27 % of energy ( % E ) as protein , 45%E as carbohydrate ) or a lower-protein ( LP ) diet ( 16%E as protein , 57%E as carbohydrate).SUBJECTS : A total of 36 obese nondiabetic volunteers with hyperinsulinemia ( 10 males/26 females , aged 34–65 y , BMI 28–43 kg/m2 , fasting insulin 12–45 mU/l ) . MEASUREMENTS : Body weight and composition , TEE , REE , and RQ were measured at baseline and at week 16 . In addition , the TEF to an HP or LP meal was determined for 3 h , at baseline and at week 16 . RESULTS : After 16 weeks , weight loss was similar in response to each diet ; the overall decrease was 7.9±0.6 kg ( P<0.001 ) , of which 6.8±0.5 kg was fat ( P<0.001 ) . REE fell similarly with each diet ; the overall decrease was 719±106 kJ/day ( P<0.001 ) . The TEF was 2 % greater after the HP than after the LP meal at baseline ( P<0.01 ) and 0.8 % greater at week 16 ( P=0.35 ) . After 16 weeks , the TEF was not reduced in either dietary group . There was no change in TEE after 16 weeks . CONCLUSION : In subjects with hyperinsulinemia an energy-restrictive diet containing an increased protein-to-carbohydrate ratio does not enhance weight loss or significantly affect energy expenditure . Caloric restriction , rather than the macronutrient composition of the diet , is the most important determinant of weight loss 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 OBJECTIVE To evaluate the effects of two low-fat hypocaloric diets differing in the carbohydrate-to-protein ratio , with and without resistance exercise training ( RT ) , on weight loss , body composition , and cardiovascular disease ( CVD ) risk outcomes in overweight/obese patients with type 2 diabetes . RESEARCH DESIGN AND METHODS A total of 83 men and women with type 2 diabetes ( aged 56.1 ± 7.5 years , BMI 35.4 ± 4.6 kg/m2 ) were r and omly assigned to an isocaloric , energy-restricted diet ( female subjects 6 MJ/day , male subjects 7 MJ/day ) of either st and ard carbohydrate ( CON ; carbohydrate : protein : fat 53:19:26 ) or high protein ( HP ; 43:33:22 ) , with or without supervised RT ( 3 days/week ) for 16 weeks . Body weight and composition , waist circumference ( WC ) , and cardiometabolic risk markers were assessed . RESULTS Fifty-nine participants completed the study . There was a significant group effect ( P ≤ 0.04 ) for body weight , fat mass , and WC with the greatest reductions occuring in HP+RT ( weight [ CON : −8.6 ± 4.6 kg , HP : −9.0 ± 4.8 kg , CON+RT : −10.5 ± 5.1 kg , HP+RT : −13.8 ± 6.0 kg ] , fat mass [ CON : −6.4 ± 3.4 kg , HP : −6.7 ± 4.0 kg , CON+RT : −7.9 ± 3.7 kg , HP+RT : −11.1 ± 3.7 kg ] , and WC [ CON : −8.2 ± 4.6 cm , HP : −8.9 ± 3.9 cm , CON+RT : −11.3 ± 4.6 cm , HP+RT : −13.7 ± 4.6 cm ] ) . There was an overall reduction ( P < 0.001 ) in fat-free mass ( −2.0 ± 2.3 kg ) , blood pressure ( −15/8 ± 10/6 mmHg ) , glucose ( −2.1 ± 2.2 mmol/l ) , insulin ( −4.7 ± 5.4 mU/l ) , A1C ( −1.25 ± 0.94 % ) , triglycerides ( −0.47 ± 0.81 mmol/l ) , total cholesterol ( −0.67 ± 0.69 mmol/l ) , and LDL cholesterol ( −0.37 ± 0.53 mmol/l ) , with no difference between groups ( P ≥ 0.17 ) . CONCLUSIONS An energy-restricted HP diet combined with RT achieved greater weight loss and more favorable changes in body composition . All treatments had similar improvements in glycemic control and CVD risk markers 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 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 OBJECTIVE To determine the effect of a high-protein ( HP ) weight loss diet compared with a lower-protein ( LP ) diet on fat and lean tissue and fasting and postpr and ial glucose and insulin concentrations . RESEARCH DESIGN AND METHODS Replacing dietary protein for carbohydrate ( CHO ) during energy restriction and weight loss has been effective in sparing lean mass and improving insulin sensitivity in obese subjects but has not been tested in subjects with type 2 diabetes . We compared an HP diet ( 28 % protein , 42 % CHO , 28 % fat [ 8 % saturated fatty acids , 12 % monounsaturated fatty acids , 5 % polyunsaturated fatty acids ] ) with an LP diet ( 16 % protein , 55 % CHO , 26 % fat [ 8 % saturated fatty acids , 11 % monounsaturated fatty acids , 5 % polyunsaturated fatty acids ] ) in 54 obese men and women with type 2 diabetes during 8 weeks of energy restriction ( 1,600 kcal ) and 4 weeks of energy balance . Body composition was determined by dual-energy X-ray absorptiometry at weeks 0 and 12 . RESULTS Overall , weight loss of 5.2 + /- 1.8 kg was achieved independently of diet composition . However , women on the HP diet lost significantly more total ( 5.3 vs. 2.8 kg , P=0.009 ) and abdominal ( 1.3 vs. 0.7 kg , P=0.006 ) fat compared with the women on the LP diet , whereas , in men , there was no difference in fat loss between diets ( 3.9 vs. 5.1 kg ) . Total lean mass decreased in all subjects independently of diet composition . LDL cholesterol reduction was significantly greater on the HP diet ( 5.7 % ) than on the LP diet ( 2.7 % ) ( P < 0.01 ) . CONCLUSIONS Both dietary patterns result ed in improvements in the cardiovascular disease ( CVD ) risk profile as a consequence of weight loss . However , the greater reductions in total and abdominal fat mass in women and greater LDL cholesterol reduction observed in both sexes on the HP diet suggest that it is a valid diet choice for reducing CVD risk in type 2 diabetes OBJECTIVE : To test the hypothesis that hyperinsulinemic obese subjects would respond differently to changes in the composition of hypoenergetic diets . DESIGN : A 4-week r and omized dietary intervention trial . SUBJECTS : Thirteen male obese hyperinsulinemic normoglycemic subjects were divided into two groups and fed hypoenergetic diets providing 80 % of their resting energy expenditure ( REE ) . One group received a high-protein diet ( HP ; 45 % protein , 25 % carbohydrates , and 30 % fat as percent of dietary energy ) and the other a high-carbohydrate diet ( HC ; 12 % protein , 58 % carbohydrates and 30 % fat ) . MEASUREMENTS : Anthropometry , body composition , fasting serum insulin and lipids , and REE were performed before and after the feeding period . RESULTS : Weight loss was higher in the HP than HC group ( 8.3±0.7 vs 6.0±0.6 kg , P<0.05 ) . There was a decrease in body fat in both groups , whereas body water decreased significantly more in the HP group . REE decreased more in the HC than the HP group ( −384.3±84.6 vs −132.3±51.0 kcal , P<0.05 ) . Serum total cholesterol , triglycerides and LDL cholesterol decreased significantly to a similar extent in both diet groups , while HDL cholesterol was decreased significantly only in the HP group . Mean fasting insulin decreased significantly in both diet groups and reached the normal range only in the HP group . CONCLUSION : A low-carbohydrate ( LC ) , HP hypoenergetic diet could be the diet composition of choice for a weight-reducing regimen in obese hyperinsulinemic subjects We have recently reported that obese women r and omized to a low-carbohydrate diet  lost more than twice as much weight as those following a low-fat diet over 6 months . The difference in weight loss was not explained by differences in energy intake because women on the two diets reported similar daily energy consumption . We hypothesized that chronic ingestion of a low-carbohydrate diet increases energy expenditure relative to a low-fat diet and that this accounts for the differential weight loss . To study this question , 50 healthy , moderately obese ( body mass index , 33.2 + /- 0.28 kg/m(2 ) ) women were r and omized to 4 months of an  ad libitum low-carbohydrate diet or an energy-restricted , low-fat diet .  Resting energy expenditure ( REE ) was measured by indirect calorimetry at baseline , 2 months , and 4 months . Physical activity was estimated by pedometers . The thermic effect of food ( TEF ) in response to low-fat and low-carbohydrate breakfasts was assessed over 5 h in a subset of subjects . Forty women completed the trial . The low-carbohydrate group lost more weight ( 9.79 + /- 0.71 vs. 6.14 + /- 0.91 kg ; P < 0.05 ) and more body fat ( 6.20 + /- 0.67 vs. 3.23 + /- 0.67 kg ; P < 0.05 ) than the low-fat group . There were no differences in energy intake between the diet groups as reported on 3-d food records at the conclusion of the study ( 1422 + /- 73 vs. 1530 + /- 102 kcal ; 5954 + /- 306 vs. 6406 + /- 427 kJ ) . Mean REE in the two groups was comparable at baseline , decreased with weight loss , and did not differ at 2 or 4 months . The low-fat meal caused a greater 5-h increase in TEF than did the low-carbohydrate meal ( 53 + /- 9 vs. 31 + /- 5 kcal ; 222 + /- 38 vs. 130 + /- 21 kJ ; P = 0.017 ) . Estimates of physical activity were stable in the dieters during the study and did not differ between groups . These results confirm that short-term weight loss is greater in obese women on a  low-carbohydrate diet than in those on a low-fat diet even when reported food intake is similar . The differential weight loss is not explained by differences in REE , TEF , or physical activity and likely reflects underreporting of food consumption by the low-fat dieters OBJECTIVE We performed this study as a pilot experiment to investigate the short term effects of two diets of varying composition on weight loss as the primary outcome in obese women with polycystic ovary syndrome ( PCOS ) seeking fertility . DESIGN R and omized clinical trial . SETTING Academic medical center . PATIENT(S ) Thirty-five obese women with PCOS . INTERVENTION(S ) We examined the effects of a 1-month dietary intervention on the PCOS phenotype . Participants were r and omized to one of two energy-restricted diets ; high protein ( HP : 30 % protein , 40 % carbohydrate , and 30 % fat ) or high carbohydrate ( HC : 15 % protein , 55 % carbohydrate , and 30 % fat ) . The fat content was held constant in both diets . MAIN OUTCOME MEASURE(S ) Primary - change in body weight ; Secondary - biometric , hormonal , lipid and lipoprotein , and markers of glucose homeostasis and energy metabolism . RESULT ( S ) Twenty-six women completed the study . Both the HP ( -3.7 + /- 1.9 kg ) and HC ( -4.4 + /- 1.5 kg ) diets result ed in significant weight loss , but there was no significant difference in mean weight loss between the two groups . There were also no differences between diets on a variety of measures including circulating and rogens , measures of glucose metabolism , and leptin . However , the effects of a hypocaloric diet per se on improving metabolic and reproductive abnormalities in a group of PCOS women were marked by a decline in circulating and rogens ( P=.03 ) , fasting and area under the curve ( AUC ) insulins ( P<.05 ) on a 3-hour oral glucose tolerance test ( OGTT ) , and fasting and AUC leptin levels ( P<.0001 ) . There was a high prevalence of menstrual bleeding during the trial ( 14 out of 26 patients ) . CONCLUSION ( S ) Those who completed the short-term hypocaloric diet had a significant weight loss and a significant improvement in their reproductive and metabolic abnormalities . There was no increased benefit to a high-protein diet . Future diet studies evaluating the ideal composition of a hypocaloric diet in women with PCOS will require a large study population , and will most likely require a multicenter trial 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 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 Energy restriction is a common therapeutic approach for weight reduction , but the most effective macronutrient distribution of the hypoenergetic diet as well as the role of the metabolic processes involved require further investigations . OBJECTIVE To study the effect of a high protein ( HP ) hypoenergetic diet compared with a high carbohydrate ( HC ) hypoenergetic diet on fuel utilisation changes during the weight loss process in obese women . DESIGN Eleven obese ( BMI > 30 ) women were r and omly assigned to a 10w dietary intervention study comparing HP ( 30 % protein ) or HC ( 55 % carbohydrate ) energy restricted diets providing 30 % energy fat content . Substrate utilisation was evaluated by indirect calorimetry . Body weight and composition ( Bod Pod ) and blood measurements were performed before and after weight loss . RESULTS On average , the individuals on the HP dietary group lost 4.4 kg more than those in the HC program ( p<0.50 ) , which was mainly due to a fat mass loss ( 3.7 kg , p<0.05 ) with no statistical differences in lean body mass reduction . These losses were accompanied by a significant decrease in fasting leptin in the HP group ( -52 % ; P<0.05 ) . On the other h and post-absorptive lipid oxidation decreased in the HC group ( -48 % ) and remained unchanged in the HP groups . CONCLUSIONS The replacement of some dietary carbohydrate by protein in energy restricted diets , improves weight and fat losses and specifically promotes lipid oxidation in the fasting state , without major different in lean body mass depletion CONTEXT Incidence of insulin resistance ( IR ) in Americans is steadily rising . IR may be ameliorated with < or = 5 % loss in body weight . OBJECTIVE To examine effects of 2 weight-loss diets on body weight and composition in overweight adults with IR . DESIGN Participants r and omly assigned to a high-protein , low-fat ( HPLF ) or a high-carbohydrate , low-fat ( HCLF ) diet for 8 weeks . SETTING All meals prepared and weighed in the metabolic kitchen at Arizona State University . Lunch consumed on-site ; all other meals packaged for home consumption . PATIENTS Twenty overweight , healthy participants with elevated fasting serum insulin ( > or = 15 microU/L ) were recruited . INTERVENTIONS Both diets were low-fat ( 27 % kcal from fat ; < 7 % saturated , < or = 10 % monounsaturated , and < or = 10 % polyunsaturated ) and energy-restricted ( energy levels were 1200 , 1500 , 1700 or 2000 kcal ) ; HPLF : 32 % protein , 41 % carbohydrate ; HCLF : 59 % carbohydrate , 14 % protein . Energy levels were assigned on the basis of participant 's resting metabolic rate . MAIN OUTCOME MEASURES Body composition , etabolic indices , fasting plasma glucose , and insulin . RESULTS No significant differences were found in the main outcome measures between the diets . Body weight ( HPLF : -4.9 kg ; HCLF : -4.0 kg ) and total percent body fat ( HPLF : -1.5 % ; HCLF : -0.4 % ) significantly reduced from baseline to week 8 ( P = .005 and P = .035 , respectively ) . CONCLUSION Both diets promoted > or = 5 % loss in body weight and significantly reduced percent body fat
target: Compared with an energy-restricted SP diet , an isocalorically prescribed HP diet provides modest benefits for reductions in body weight , FM , and triglycerides and for mitigating reductions in FFM and REE
background: BACKGROUND It is currently unclear whether altering the carbohydrate-to-protein ratio of low-fat , energy-restricted diets augments weight loss and cardiometabolic risk markers .
  OBJECTIVE The objective was to conduct a systematic review and meta- analysis of studies that compared energy-restricted , isocaloric , high-protein , low-fat ( HP ) diets with st and ard-protein , low-fat ( SP ) diets on weight loss , body composition , resting energy expenditure ( REE ) , satiety and appetite , and cardiometabolic risk factors .