The Effect Of Low-carbohydrate Diet And Low-calorie Diet On Weight Loss In Overweight Or Obese Individuals

BackgroundWith the development of society and economy,people’s daily diet and calorie increase,as well as long-term sedentary,lack of exercise and other lifestyle changes,excessive accumulation of fat in the body leads to an increase in the incidence of overweight and obesity.According to statistics,a total of 1.9 billion people in the world are classified as overweight,including 600 million obese people,China has surpassed the United States in obesity,becoming the world’s largest obese country.Obesity not only leads to a variety of chronic non-communicable diseases,including type 2 diabetes,cardiovascular disease,osteoarthritis and cancer,but also poses a serious economic burden on society.Therefore,curbing the occurrence of obesity and its complications and seeking a healthy,effective and safe method of weight loss is an urgent problem to be solved at present.Diet control,physical exercise,drug use,gastrointestinal volume reduction surgery,and the recent development of intestinal microflora transplantation are the main methods of obesity treatment,each of which has its own advantages and disadvantages.Weight loss is a systematic project that requires long-term adherence,and medical nutrition therapy is always the protagonist and foundation.Calorie-restricted diet(CRD)and low-carbohydrate diet(LCD)/ketogenic diet calorie-restricted diet on reducing body weight,visceral fat area,blood lipid level,improving chronic low-grade inflammation,insulin resistance and the risk of atherosclerosis have been proved by many studies at home and abroad.Caloric restriction diet is recognized as an effective way of weight loss in ADA guidelines,and medical nutrition therapy with caloric restriction as its core is effective.Most studies have shown that low-carbohydrate diet not only has significant weight loss effect,but also can improve the glucose and lipid metabolism of obese people.But the two diets are controversial in academia:the ADA guidelines point out that even with different amounts of carbohydrates,proteins and fats,the effects of weight loss are the same when calorie limits are the same;Atkins believes that under the conditions of limiting carbohydrates,even without limiting the dietary intake of calories,it can achieve an effective weight loss effect.And under the condition of limiting calories,whether or not limiting carbohydrates will bring about different weight loss effects,and whether limiting calories has a better weight loss effect than not limiting calories under the condition of limiting carbohydrates.It has not been reported whether there is one diet affecting the weight loss of the other diet,such as synergistic or additive effects.Therefore,if there is interaction between low-carbohydrate diet and calorie-limiting diet in weight loss of overweight/obesity population,it can provide a more reasonable and healthy weight management diet pattern for overweight/obesity population.In order to achieve safe,effective weight loss and improve related glucose and lipid metabolism abnormalities.Objective(1)to explore whether there are synergistic and interactive effects between LCD and CRD for overweight or obeses(OW/OB);(2)to observe the effect of LCD and CRD on weight loss in overweight or(3)to investigate the effect of LCD and CRD on body and metabolic parameters.MethodsIn this study,305 overweight/obesity patients were recruited from 13 research centers in Guangdong Province.After screening,290 subjects were randomly divided into four dietary intervention groups according to the ratio of 1:1:1:1,290 subjects met the criteria.Group A had no calorie-limited normal structure diet(NC),B group had low carbohydrate diet,(LCD),C group had calorie-restricted diet,(CRD)and D group had low-carbohydrate diet and calorie-restriction(LCD+CR).All subjects had 12 weeks of dietary intervention.Before and after intervention,weight(WT),body mass index(BMI),visceral fat area(VFA),body fat percentage(BFR)and ratio of waist to hip circumference(WHR)were measured,at same time,detecting fasting blood glucose(FBG),fasting insulin(FIns),renal function,liver function,homeostasis model insulin resistance index(HOMA-IR)and ten-year risk score for coronary heart disease were evaluated.Group A was used as experimental control group,group B,C,D as intervention group,and baseline control value was 0 weeks in each group.All the data were analyzed by SAS9.4 software.The covariance analysis based on factorial design was applied to the main endpoint index BMI based on the baseline value as a covariable.For the quantitative index of secondary index,the covariance analysis under factorial design will be adopted with the base line value as covariable.The measurement data of normal distribution compared with baseline were compared by Chi-square test and paired-sample t-test before and after treatment.Wilcoxon signed rank test was used for intra-group comparison of measurement data of non-normal distribution.The difference was statistically significant(P<0.05).ResultsCompared with pre-intervention,after 12 weeks of intervention,BMI in NC,LCD,CRD and LCD+CR group decreased respectively by(0.61 ±0.89)kg/m2,(2.32±1.31)kg/m2,(1.19 ±0.97)kg/m2,(2.96 ± 1.15)kg/m2.There was a significant difference in the amount of BMI among the four groups(P<0.001),among which the decrease of LCD+CR was the most obvious.The BFR,VFA,WHR of overweight/obesity individuals in LCD,CRD,LCD+CR group was lower than that in baseline.There was significant difference in BFR,VFA,WHR content among the four groups(P<0.001),especially in LCD+CR group,which was the most significant difference between the four groups(P<0.05).However,there was no interaction between calorie-restricted diet and dietary structure(F=0.004,P=0.950).Compared with baseline,the level of HOMA-IR,UA in,LCD+CR group was significantly lower than baseline,and the TG level in LCD+CR group was significantly lower than that in baseline.(P<0.05).There was significant difference in the amount of FIns,HOMA-IR,TG,UA among the three groups(P<0 05).The HDL-C in LCD group and LCD+CR group was significantly higher than that in baseline,and there was a significant difference in 10-year risk score of coronary heart disease between the two groups.There was no significant difference in TC,LDL-C,HDL-C,AST,ALT,TB and other indexes among the three groups(P>0.05).Thirty-one participants dropped out of the study during the intervention.ConclusionShort-term CRD,LCD and LCD CR had the effect of weight loss in overweight/obesity individuals,and LCD+CR group was the most obvious,and LCD had better weight loss effect than CRD.Limiting carbohydrate intake at the same time can achieve better weight loss under the condition of calorie restriction,but there is no interaction between them,that is,the weight loss effects of the two dietary patterns are independent of each other.LCD and LCD+CR can reduce BFR,VFA,WHR and change the body posture of overweight/obese individuals,and at the same time reduce the level of TG,FIns,improve insulin resistance,fatty liver,and reduce the occurrence of cardiovascular diseases.