Lifestyle-related diseases are the outcome of both nutritional and genetic factors. The genetic factors are due mainly to single-nucleotide polymorphisms (SNPs). SNPs including beta-adrenergic receptor, uncoupling proteins 2 and 3p, PPAR-gamma, and leptin receptor are responsible for obesity and diabetes. Westernization of lifestyle and diet has a strong impact. We have studied SNPs in mongoloids because of their rapid increase in diabetes resulting from westernization. SNPs responsible for saving energy-the so-called called “thrifty SNPs” (Biochem Biophys Res Commun 295: 207-222, 2002)-were found in PPAR-gamma 2, UCP3 promoter, leptin receptor etc. Using mailed swab DNA samples, we also analyzed SNPs of individuals who had been educated 25-31 years previously. Despite differences in SNPs (UCP3p, UCP2, apoE and mtDNA), the special dietary habits (four-group point method) and exercise practiced by these individuals prevented most of the lifestyle-related diseases. A diabetes prevention program to encourage effective habit change is an important activity of registered dieticians.