You Need 8 Glasses of Water a Day

The rigid rule of eight glasses a day lacks scientific backing: hydration needs vary widely based on activity, climate, and diet. The National Academies of Sciences reports adequate intake averages 3.7 liters daily for men and 2.7 liters for women, with food providing roughly 20% of that total. This myth outperforms #12 in persistence, yet studies confirm that individual factors dictate actual requirements, making a one-size-fits-all guideline inaccurate for everyone.