While autophagy does correlate with fasting and some studies link it to health markers, it should be noted that it usually takes at least 18 hours of continued fasting to even start and only goes into full swing after 48 to 72 hours. It is also an extreme cell response that is associated with high levels of cellular stress, which might have understudied long term detrimental effects. A simple calorie reduction either by eating fewer highly processed meals or regular intense exercise is much more universally accepted as longevity boosting, because it combats overweight, which is by far the most common disease that shortens general lifespan in the western world. There's really no good reason to force your body through these extreme diets. Don't be overweight, don't smoke, don't drink alcohol, maybe go easy on junk food and maybe do some exercise. And get your regular medical check-ups. Then you're already at the pinnacle of clinical longevity science. There is no actual anti aging drug yet that has a proven effect on humans. Best we have are some moderately promising monkey and small mammal studies, but they generally don't translate well.