A Meta-analysis Of The Obesity Diet Therapy

Objective: To evaluate the effects of low carbohydrate diets and low fat diets which on weight,blood pressure and lipid metabolism at short term(within 6 months) and long term(1 year).Methods: We use PubMed to search for literature,and collected results of 8 studies,then use RevMan 5.0 do a meta-analysis.Results:(1)Short term:low carbohydrate diets has better effects on decreasing weight(WMD is -1.28kg,95%CI(confidence interval,CI)is[-1.63,-0.93]kg,P<0.00001) ,TG level(WMD is -14.67mg/dl(-0.17mmol/L),95%CI is [-22.48,-6.85]mg/dl(-0.25,-0.08mmol/L),P=0.0002),blood pressure (Systolic blood pressure :WMD is -4.04mmHg,95%CI is [-6.00,-2.09]mmHg,P<0.0001;Diastolic blood pressure:WMD is -2.47mmHg,95%CI is [-4.86,-0.08]mmHg,P=0.04)and increasing HDL-C level(WMD is 6.44mg/dl(0.17mmol/L),95%CI is [3.29,9.58]mg/dl(0.09,0.25mmol/L),P<0.0001) than low fat diets,but it is inferior to low fat diets on decrease TC level(WMD is 7.61mg/dl (0.20mmol/L),95%CI is [0.86,14.36]mg/dl(0.02,0.37mmol/L),P=0.03) and LDL-C level(WMD is 3.43mg/dl(0.09mmol/L),95%CI is [0.25,6.62]mg/dl(0.006,0.17mmol/L),P=0.03).(2)Long term:They have not difference on decreasing weight (WMD is -0.60kg,95%CI is [-1.63,-0.42]kg,P=0.25)and blood pressure(Systolic blood pressure :WMD is -0.68mmHg,95%CI is [-4.59,3.24]mmHg,P=0.73;Diastolic blood pressure:WMD is -1.20mmHg,95%CI is [-2.50,-0.10]mmHg,P=0.07).Low carbohydrate diets has better effects on decreasing TG level (WMD is -21.36mg/dl(-0.24mmol/L),95%CI is [-29.73,-12.99]mg/dl(-0.34,-0.15mmol/L),P<0.00001)and increasing HDL-C level (WMD is 3.62mg/dl(0.09mmol/L),95%CI is [1.22,6.01]mg/dl(0.03,0.16mmol/L),P=0.003)than low fat diets,however,it is inferior to low fat diets on decreasing TC level (WMD is 6.28mg/dl ( 0.16mmol/L ), 95%CI is [2.22 , 10.35]mg/dl ( 0.06 ,0.27mmol/L ), P=0.002 ) and LDL-C level ( WMD is 4.65mg/dl(0.12mmol/L),95%CI is [1.09,8.21]mg/d(l0.03,0.21mmol/L),P=0.01).Conclusion: In short term,low carbohydrate diets have lost more weight and decreased more blood pressure than low fat diets,but have not difference in long term.And no matter in short term or long term,low carbohydrate diets is superior to low fat diets on decreasing TG level and increasing HDL-C level ,but it is inferior to low fat diets on decreasing TC level and LDL-C level .