In 2003, after a career in scientific research and upper management, the former marathon runner decided - after 20 years of a sedentary lifestyle - to reconnect with a serious sport. In 2008, after having successfully competed in several long-distance cycling events, He wrote a book about his experience called "Herausforderung Race Across America" ("Challenge Race Across America") and produced a DVD called 'Du musst nicht siegen, um zu gewinnen. (English translation: "You need no victory to be a winner") on his own. Since 2011, Nehls has published several books on the necessary behavioral changes required for healthy aging from an evolutionary history point of view. First
"The Methuselah-Strategy" then with
Alzheimer-Lüge (English translation: "The Alzheimer's Lie") and
Alzheimer ist heilbar (English translation: "Alzheimer's can be cured") two books about
Alzheimer's disease, in which he presents his theory about the development of this special form of dementia from
evolutionary history of life and
systems biology point of view. The German biochemist
Christian Haass criticized Nehls' statements on Alzheimer's disease for the Alzheimer-Gesellschaft München (Munich Alzheimer Society) in 2015 as misleading and harmful for those affected, that behavior and preventive measures did have an influence on the onset and progression of the disease. In principle, however, Alzheimer's disease cannot be prevented in this way. “Preventing Alzheimer’s disease simply through a correct lifestyle” is “too nice a pipe dream” and “does not do justice to the 1.2 million people affected in Germany.” Such claims are “well suited for
pseudo-scientific treatises, but they are... On closer inspection, it only serves the author’s vanity.” In 2021, the
bioethiciane Silke Schicktanz described Nehls as a “
popular science author”, whose content is more or less ignored by the scientific mainstream, with his focus on prediction and preventing dementia (as opposed to curing it) is illustrative of the contemporary discourse in Germany on the topic. Dr. Nehls' article titled "Unified theory of Alzheimer's disease (UTAD): implications for prevention and curative therapy" was internationally published in the
Journal of Molecular Psychiatry. And for his breakthrough discovery regarding the development, prevention and therapy of Alzheimer's disease, he received the 2015 Hanse-Award for Psychiatry from the University of Rostock, Germany. ==Controversies and criticism==