At 120 kg with moderate activity, you need approximately 4.8 liters (about 19 glasses) of water per day. This is more than double generic guidelines — but it's what your body genuinely requires.
At 120 kg (265 lbs), your baseline water need is 3,960 ml per day — essentially 4 liters before any adjustments. With moderate activity, this rises to approximately 4.8 liters. At this weight, there is no meaningful generic guideline that applies to you. Your hydration must be personalized.
Consider what your body manages daily: maintaining 8–9 liters of blood, hydrating roughly 60 trillion cells, cooling a body that generates substantial metabolic heat, and filtering approximately 180 liters of fluid through your kidneys (most of which is reabsorbed). Water is the enabler of all of this.
4.8 liters sounds intimidating until you break it down: across 16 waking hours, it's 300 ml per hour — one standard glass. You're not doing anything dramatic; you're maintaining a steady, gentle inflow that matches your body's constant outflow.
Most people at 120 kg who begin meeting their actual target discover that they were so accustomed to mild dehydration that they had forgotten what properly hydrated feels like. The improvement in energy, mental clarity, and physical comfort is often described as transformative.
At 120 kg, proper hydration provides compounding benefits across multiple systems:
If you've been drinking 2–3 liters daily at 120 kg, don't jump to 4.8 liters overnight. Increase by 500 ml per day, giving your kidneys and bladder time to adjust. Most people reach their target within 7–10 days of gradual increase, and the adjustment period is marked by more frequent urination that normalizes as your body adapts to adequate hydration.
Absolutely. At 120 kg (265 lbs), your body contains 60–72 liters of water and turns over a significant portion daily. 4.8 liters of intake barely keeps pace with your losses through urine, sweat, breathing, and digestion.