This surprise bestseller in Germany will change work and play habits -- and lives. It contradicts much popular thinking about how to lead a long, healthy and happy life, and it does so based on scientifically grounded arguments and research which shows that the key to good health, success and longevity is the CONSERVATION of life energy. On the basis of the scientifically recognized Metabolic Theory, this book develops a program that can work for everyone. It explains the scientific correlation between life energy and longevity in an easy-to-understand way. The authors have found through their research that older but hearty and active people often do not follow the regimen we have believed was the secret to a long life. They are calm in every situation; they enjoy life, play sports in moderation, eat little and do not waste their valuable life energy. They are not excessively ambitious. All this seems to be the secret to vitality and good health. The book contains valuable tips and advice for everyone who wants to stay healthy and live longer, energy-saving suggestions about eating, working and exercising, and quizzes to test your stress level, life energy and physical well-being.