Obesity rate is increasing in both developed and developing countries.Many scholars agree that it has to do more with environmental factors.I am interested to know the role of genetics, in quantitative terms.
gene-by-environment interactions are not yet sufficiently understood! I hope that the following papers helps your work in some small way. Be well!! Martin
Stunkard AJ, Sørensen TI, Hanis C, Teasdale TW, Chakraborty R, Schull WJ, Schulsinger F. An adoption study of human obesity. N Engl J Med. 1986;314(4):193-8. https://www.researchgate.net/publication/19219648_An_Adoption_Study_of_Human_Obesity
Speliotes EK, Willer CJ, Berndt SI, et al. Association analyses of 249,796 individuals reveal 18 new loci associated with body mass index. Nat Genet. 2010;42(11):937-48. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3014648/pdf/nihms237282.pdf
Manco M, Dallapiccola B. Genetics of pediatric obesity. Pediatrics. 2012;130(1):123-33. http://pediatrics.aappublications.org/content/130/1/123.full.pdf+html
Lee YS. Genetics of nonsyndromic obesity. Curr Opin Pediatr. 2013;25(6):666-73. http://journals.lww.com/co-pediatrics/Abstract/2013/12000/Genetics_of_nonsyndromic_obesity.6.aspx
Liu CT, Monda KL, Taylor KC, et al. Genome-wide association of body fat distribution in African ancestry populations suggests new loci. PLoS Genet. 2013;9(8):e1003681. http://www.plosgenetics.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pgen.1003681&representation=PDF
Shabana, Hasnain S. Effect of the Common Fat Mass and Obesity Associated Gene Variants on Obesity in Pakistani Population: A Case-Control Study. Biomed Res Int. 2015;2015:852920. http://www.hindawi.com/journals/bmri/2015/852920/
Locke AE, Kahali B, Berndt SI, et al. Genetic studies of body mass index yield new insights for obesity biology. Nature. 2015 Feb 12;518(7538):197-206. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4382211/pdf/nihms-668049.pdf
Shungin D, Winkler TW, Croteau-Chonka DC, et al. New genetic loci link adipose and insulin biology to body fat distribution. Nature. 2015;518(7538):187-96. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338562/pdf/emss-61357.pdf
Davé V, Yousefi P, Huen K, Volberg V, Holland N. Relationship between expression and methylation of obesity-related genes in children. Mutagenesis. 2015;30(3):411-20. http://ehsdiv.sph.berkeley.edu/holland/publications/files/Dave2015.pdf
Urano T, Inoue S. Recent genetic discoveries in osteoporosis, sarcopenia and obesity. Endocr J. 2015;62(6):475-84. https://www.jstage.jst.go.jp/article/endocrj/62/6/62_EJ15-0154/_pdf