The Research Of Evaluation Method About Weight Loss Effect Based On Bioelectrical Impedance

Nowadays, obesity has already been widely concerned with the number of obesitycontinuously increasing in the world. The essence of obesity is the amount of fat that beaccumulated in body, however the core of weight-loss is to effectively reduce the fat inbody. Therefore we can estimate the effect in the process of weight loss through toevaluate the content and distribution of body’s fat. Now there are many existing methodsfor detection of the content and distribution of body’s fat, but the most methods cannot bewidely applied to the daily evaluation because of the low accuracy, expensive equipment,complex procedure, higher environment.Bioelectrical impedance analysis (BIA) is an indirect method for body compositionassessment. The basic idea is that current will flow along the low resistance and easilyconductive body fluid when weak AC signal into the human body. Water determines theconductive of current path, and the conductivity can be expressed by the impedance. A lotof experimental data show that there is a statistical relationship between bioelectricalimpedance characteristics and body composition. This is the principle of bodycomposition measurement technology based on bioelectrical impedance.According to the principle of using BIA technology to analysis body composition,this paper presents a method for detection of body fat content and distribution based onbioelectrical impedance, and apply this method to evaluation of daily weight loss effectThe main research contents of this article include: the first is the design of multi-frequencyimpedance measurement system. The design of the system adopts a way of combiningupper and lower computer. The lower computer completes the design of the bioelectricalimpedance measurement system based on high precision impedance measurement chipAD5933to simulate font four electrodes. This design realizes the multi-frequencymeasurement range from1kHz~100kHz and the collection data will be send to uppercomputer by the USB to Serial port module. The upper computer completes the design ofthe application program for automated data acquisition device based on windows. Itrealizes the friendly human-machine interaction and the data management. Secondly, we established the model of body segments impedance and can get the impedance of theupper limb、lower limb、trunk through this model.The main experiment content of this article contains two aspects. Firstly, we willverify the reproducibility and validity of experimental instrument. Secondly, we willverify effectiveness and feasibility of using the bioelectrical impedance to indirectly judgethe weight loss result. Through the analysis of fat content and distribution forexperimental subject before and after the experiment, we proved that the BIA method inthis paper is more effective than by body weight or the effectiveness of BMI to determinethe weight loss effect.