A scientist has revealed his top tips for slowing down the aging process, saying people should take care of their teeth and avoid over-exercising if they want to live longer lives. Andrew Steele, a computational biologist and longevity expert, argues in his new book, Ageless: The New Science of Getting Older Without Getting Old, that people have more control over their aging process than they realize. The London-based author appeared on the Today show on Tuesday to promote his research, explaining that interventions such as eating a healthy diet, avoiding smoking, and getting moderate exercise can all slow down the aging process and prevent different diseases.