Water only best for autophagy.
Ive never done a pure water fast myself. I’ve always had stuff like sugar free energy drinks as I still lift weights and keep active so the caffine boost hits you hard when fasting.
Had great results for fat loss but the sweeteners etc can mess with your taste buds, hormones making you crave more and more so be careful if consuming stuff like this.
Unsweetened soya milk is about 200/300 cals per liter… So be careful not to use more than half a liter a day imo. Best just do black coffee if you can
I’ve yet to find any studies that show what interferes with autophagy. Maybe it’s not measurable. I know Dr Longo has that fasting mimicking diet that has like 500 calories in it. I also know that Buchinger fasting method allows for 200-250 calories per day. I think if the human body was so inefficient as to stop autophagy for consuming a few calories worth of carbs/protein/fats, then our species wouldn’t have survived this long lol.