Skip to main content
Log in

Validity of Leg-to-Leg Bioelectrical Impedance Analysis to Estimate Body Fat in Obesity

  • Clinical Research
  • Published:
Obesity Surgery Aims and scope Submit manuscript



Bioelectrical impedance analysis (BIA) is a safe and easy method of assessing body composition. Its accuracy to predict fat mass (FM) in obesity and the change in FM following weight loss is questioned. Our objective was to compare leg-to-leg BIA to dual-energy X-ray absorptiometry (DXA) in the assessment of FM in a large population, the changes in FM after Roux-en-Y gastric bypass (RYGB) and to estimate between-method differences (bias) and limits of agreement.


BIA (Tanita BC-420MA) and DXA (Hologic Discovery W) were used in 5,740 consecutive patients (mean BMI, 37.7 ± 8.2 kg/m2) examined in a clinical nutrition department and in 72 women undergoing RYGB (BMI, 47.2 ± 7.2 kg/m2). Analyses included correlations between methods and Bland Altman analysis.


In the entire population, BIA significantly overestimated FM in comparison with DXA (1.1 ± 6.1 kg, 0.8 ± 5.6%). FM estimates by each method were significantly correlated in absolute value (kg; r 2 = 0.9 in the whole population), and in percentage (r 2 = 0.6). However, wide limits of agreement were observed. In surgery patients, BIA significantly overestimated FM both before and 12 months after bypass. BIA significantly overestimated changes in FM after RYGB at 3 months (2.9 ± 5.0 kg) and at 12 months (1.9 ± 3.9 kg) but not at 6 months (0.9 ± 5.0 kg; p = 0.08). Estimates of changes in FM by each method were significantly correlated (r 2 = 0.4, 0.6, and 0.9, respectively).


According to the wide limits of agreement, BIA seems more interesting for epidemiological rather than individual use to evaluate body FM and FM changes in obese women undergoing RYGB.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2

Similar content being viewed by others



Bioelectrical impedance analysis


Dual-energy X-ray absorptiometry


Roux-en-Y gastric bypass


Body mass index


Fat-free mass


Fat mass






Total body water


  1. Ciangura C, Bouillot JL, Lloret-Linares C, et al. Dynamics of change in total and regional body composition after gastric bypass in obese patients. Obesity (Silver Spring). 2009;18(4):760–5.

    Article  Google Scholar 

  2. Cox-Reijven PL, van Kreel B, Soeters PB. Accuracy of bioelectrical impedance spectroscopy in measuring changes in body composition during severe weight loss. JPEN J Parenter Enteral Nutr. 2002;26:120–7.

    Article  PubMed  Google Scholar 

  3. Das SK. Body composition measurement in severe obesity. Curr Opin Clin Nutr Metab Care. 2005;8:602–6.

    Article  PubMed  Google Scholar 

  4. Das SK, Roberts SB, Kehayias JJ, et al. Body composition assessment in extreme obesity and after massive weight loss induced by gastric bypass surgery. Am J Physiol Endocrinol Metab. 2003;284:E1080–8.

    PubMed  CAS  Google Scholar 

  5. Lee SY, Gallagher D. Assessment methods in human body composition. Curr Opin Clin Nutr Metab Care. 2008;11:566–72.

    Article  PubMed  Google Scholar 

  6. Savastano S, Belfiore A, Di Somma C, et al. Validity of bioelectrical impedance analysis to estimate body composition changes after bariatric surgery in premenopausal morbidly women. Obes Surg. 2009;20:332–9.

    Article  PubMed  Google Scholar 

  7. LaForgia J, Dollman J, Dale MJ, et al. Validation of DXA body composition estimates in obese men and women. Obesity (Silver Spring). 2009;17:821–6.

    Article  Google Scholar 

  8. Kyle UG, Bosaeus I, De Lorenzo AD, et al. Bioelectrical impedance analysis-part II: utilization in clinical practice. Clin Nutr. 2004;23:1430–53.

    Article  PubMed  Google Scholar 

  9. Kyle UG, Bosaeus I, De Lorenzo AD, et al. Bioelectrical impedance analysis—part I: review of principles and methods. Clin Nutr. 2004;23:1226–43.

    Article  PubMed  Google Scholar 

  10. Fried M, Hainer V, Basdevant A, et al. Inter-disciplinary European guidelines on surgery of severe obesity. Int J Obes (Lond). 2007;31:569–77.

    CAS  Google Scholar 

  11. Suter M, Giusti V, Heraief E, et al. Laparoscopic Roux-en-Y gastric bypass: initial 2-year experience. Surg Endosc. 2003;17:603–9.

    Article  PubMed  CAS  Google Scholar 

  12. Nunez C, Gallagher D, Visser M, et al. Bioimpedance analysis: evaluation of leg-to-leg system based on pressure contact footpad electrodes. Med Sci Sports Exerc. 1997;29:524–31.

    PubMed  CAS  Google Scholar 

  13. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;1:307–10.

    Article  PubMed  CAS  Google Scholar 

  14. Sun G, French CR, Martin GR, et al. Comparison of multifrequency bioelectrical impedance analysis with dual-energy X-ray absorptiometry for assessment of percentage body fat in a large, healthy population. Am J Clin Nutr. 2005;81:74–8.

    PubMed  CAS  Google Scholar 

  15. Andreoli A, Melchiorri G, De Lorenzo A, et al. Bioelectrical impedance measures in different position and vs dual-energy X-ray absorptiometry (DXA). J Sports Med Phys Fitness. 2002;42:186–9.

    PubMed  CAS  Google Scholar 

  16. Evans EM, Saunders MJ, Spano MA, et al. Body-composition changes with diet and exercise in obese women: a comparison of estimates from clinical methods and a 4-component model. Am J Clin Nutr. 1999;70:5–12.

    PubMed  CAS  Google Scholar 

  17. Frisard MI, Greenway FL, Delany JP. Comparison of methods to assess body composition changes during a period of weight loss. Obes Res. 2005;13:845–54.

    Article  PubMed  Google Scholar 

  18. Kim HJ, Gallagher D, Song MY. Comparison of body composition methods during weight loss in obese women using herbal formula. Am J Chin Med. 2005;33:851–8.

    Article  PubMed  Google Scholar 

  19. Neovius M, Hemmingsson E, Freyschuss B, et al. Bioelectrical impedance underestimates total and truncal fatness in abdominally obese women. Obesity (Silver Spring). 2006;14:1731–8.

    Article  Google Scholar 

  20. Pateyjohns IR, Brinkworth GD, Buckley JD, et al. Comparison of three bioelectrical impedance methods with DXA in overweight and obese men. Obesity (Silver Spring). 2006;14:2064–70.

    Article  Google Scholar 

  21. Thomson R, Brinkworth GD, Buckley JD, et al. Good agreement >between bioelectrical impedance and dual-energy X-ray absorptiometry for estimating changes in body composition during weight loss in overweight young women. Clin Nutr. 2007;26:771–7.

    Article  PubMed  Google Scholar 

  22. Utter AC, Nieman DC, Ward AN, et al. Use of the leg-to-leg bioelectrical impedance method in assessing body-composition change in obese women. Am J Clin Nutr. 1999;69:603–7.

    PubMed  CAS  Google Scholar 

  23. Varady KA, Santosa S, Jones PJ. Validation of hand-held bioelectrical impedance analysis with magnetic resonance imaging for the assessment of body composition in overweight women. Am J Hum Biol. 2007;19:429–33.

    Article  PubMed  Google Scholar 

  24. Newton Jr RL, Alfonso A, York-Crowe E, et al. Comparison of body composition methods in obese African-American women. Obesity (Silver Spring). 2006;14:415–22.

    Article  Google Scholar 

  25. Bray GA, DeLany JP, Harsha DW, et al. Evaluation of body fat in fatter and leaner 10-y-old African American and white children: the Baton Rouge Children’s Study. Am J Clin Nutr. 2001;73:687–702.

    PubMed  CAS  Google Scholar 

  26. Coppini LZ, Waitzberg DL, Campos AC. Limitations and validation of bioelectrical impedance analysis in morbidly obese patients. Curr Opin Clin Nutr Metab Care. 2005;8:329–32.

    Article  PubMed  Google Scholar 

  27. Deurenberg P, Weststrate JA, Hautvast JG. Changes in fat-free mass during weight loss measured by bioelectrical impedance and by densitometry. Am J Clin Nutr. 1989;49:33–6.

    PubMed  CAS  Google Scholar 

  28. Withers RT, LaForgia J, Pillans RK, et al. Comparisons of two-, three-, and four-compartment models of body composition analysis in men and women. J Appl Physiol. 1998;85:238–45.

    PubMed  CAS  Google Scholar 

  29. Friedl KE, DeLuca JP, Marchitelli LJ, et al. Reliability of body-fat estimations from a four-compartment model by using density, body water, and bone mineral measurements. Am J Clin Nutr. 1992;55:764–70.

    PubMed  CAS  Google Scholar 

  30. Fuller NJ, Jebb SA, Laskey MA, et al. Four-component model for the assessment of body composition in humans: comparison with alternative methods, and evaluation of the density and hydration of fat-free mass. Clin Sci (Lond). 1992;82:687–93.

    CAS  Google Scholar 

  31. Pietrobelli A, Wang Z, Formica C, et al. Dual-energy X-ray absorptiometry: fat estimation errors due to variation in soft tissue hydration. Am J Physiol. 1998;274:E808–16.

    PubMed  CAS  Google Scholar 

  32. Deurenberg-Yap M, Schmidt G, van Staveren WA, et al. Body fat measurement among Singaporean Chinese, Malays and Indians: a comparative study using a four-compartment model and different two-compartment models. Br J Nutr. 2001;85:491–8.

    Article  PubMed  CAS  Google Scholar 

  33. Goodsitt MM. Evaluation of a new set of calibration standards for the measurement of fat content via DPA and DXA. Med Phys. 1992;19:35–44.

    Article  PubMed  CAS  Google Scholar 

Download references


Thanks are expressed to Sophie Festis and Marianne Merlet, both at the Department of Nutrition, Pitié Salpêtrière Hospital, Paris, France, for expert technical assistance with DXA measurements. The authors are grateful to Dr. Andrew Green, general practitioner in Cheltenham (UK), for reviewing the English.

Conflict of interest


Author information

Authors and Affiliations


Corresponding author

Correspondence to Jean-Michel Oppert.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lloret Linares, C., Ciangura, C., Bouillot, JL. et al. Validity of Leg-to-Leg Bioelectrical Impedance Analysis to Estimate Body Fat in Obesity. OBES SURG 21, 917–923 (2011).

Download citation

  • Published:

  • Issue Date:

  • DOI: