We managed to convince my almost 70 years old father in law, he dropped 30+ kilos in two years. He could barely walk without getting out of breath, now he walks 20-30k steps a day, every day. We got rid of his cardiologist who kept telling him to take pills because his symptoms were just due to old age... Now he needs half the pills, and the ones he still has to take are much lower doses.

No idea if it'll have an impact on his lifespan but it definitely bought him years of health and changed his day to day life