Does drinking a lot of water really help you to lose weight?

No Unless Stops Food. The only possibly valid issue for some is that stomach fullness (doesn't last long with water) might decrease the amount they eat. The controlling issue is the amount of food & what type, not calories per-se. Sugars/carbs most rapidly stored as fat, protein moderately so, natural fats the least stored as fat. Study "taubes why we get fat", "stossel debunking food myths", taubes, attia, lustig, etc.