Abstract Human beings evolved on a diet that was balanced in the omega-6 and omega-3 essential fatty acids to which their genes were programmed to respond. Studies on gene-nutrient interactions using methods from molecular biology and genetics have clearly shown that there are genetic differences in the population, as well as differences in the frequency of genetic variations that interact with diet and influence the growth and development of humans and animals, as well as overall health and chronic disease. Nutrigenetics refers to studies on the role of genetic variants and their response to diet. For example, persons with genetic variants in the metabolism of omega-6 and omega-3 fatty acids have different levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) based on the type of genetic variant in the Fatty Acid Desaturase 1 (FADS1) and Fatty Acid Desaturase 2 (FADS2). At the same level of linoleic acid (LA) and alpha-linolenic acid (ALA) a person with a genetic variant that increases the activity of the FADS1 will have a higher AA in the red cell membrane phospholipids and a higher risk for obesity and cardiovascular disease. Nutrigenomics refers to how nutrients (diets) influence the expression of genes. For example, diets rich in omega-3 fatty acids, EPA and DHA decrease the expression of inflammatory genes and as a result decrease the risk of obesity and cardiovascular disease. Thus, through studies on Nutrigenetics/Nutrigenomics nutritional science stands at its “golden threshold” where personalized nutrition is the future, to improve an individual’s health.