More frequent cooking was associated with longer survival even in people who cooked at home fewer than five times per week and even after researchers adjusted the data for mental and physical function (the ability to grocery shop and cook) and knowledge of nutrition.
Chen, R. C., M. S. Lee, Y. H. Chang, and M. L. Wahlqvist. 2012. "Cooking frequency may enhance survival in Taiwanese elderly." Public Health Nutrition 15(7):1142-9.