This dissertation contains three papers on the health and welfare of the elderly population. Overall, these papers provide insights into the costs and challenges of providing health care to the elderly population. These papers help us understand the effects of obesity on longevity and health care, as well as better understand the benefits of social insurance. The first paper uses a micro-simulation model to estimate the longevity effects of poor health trends among younger Americans, and finds that difference in these trends can explain 92% of the difference between US and European longevity. The second paper estimates the welfare effects of Medicare Part-D from gains in market efficiency and dynamic incentives for pharmaceutical companies. It finds that these gains alone nearly cover the welfare cost of funding Medicare Part-D. The last paper presents and estimates a structural model of health, exercise, and restaurant consumption. It provides estimates for future welfare analyses of programs targeting obesity through restaurants and exercise in the elderly population. It also estimates the long run effects of making policies which make restaurant food healthier. It finds only minor effects of restaurant policies on health for the elderly. Overall, these papers further our understanding of the challenging objective of improving senior health while containing costs.