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Does Drinking Water Before Meals Help You Lose Weight?
Drinking a glass of water before meals is one of the more research-backed 'simple tricks' in weight management — not a magic fix, but genuinely supported by clinical trials.
What the research shows
In one randomized controlled trial, adults over 55 who drank about 500 ml (roughly 2 cups) of water 30 minutes before each main meal lost significantly more weight over 12 weeks than those who didn't, while following the same reduced-calorie diet. Other trials have found pre-meal water reduces the amount of food eaten at that meal by roughly 13-22%.
Why it seems to work
Water takes up space in the stomach, which can trigger a temporary sense of fullness that reduces how much you eat during the meal that follows. Drinking water instead of a sugary beverage before or with a meal also directly removes those extra calories from your day.
Its limits
The effect appears strongest in older adults and tends to be modest on its own — it's a helpful supporting habit, not a substitute for an overall calorie-appropriate diet. Long-term studies on water preloading alone (without other dietary changes) are still limited.
How to try it
Aim for roughly 500 ml of water about 20-30 minutes before your main meals, which gives it time to create a sense of fullness without simply diluting the meal itself.
Put it into practice
Try the TDEE Calculator →
Find your Total Daily Energy Expenditure.
Frequently Asked Questions
Water before the meal appears to have a stronger effect on reducing intake than water during the meal, though both are reasonable habits — the key mechanism is timing enough gap before eating for a sense of fullness to register.
Medical disclaimer
This article is for general informational and educational purposes only and isn’t a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your specific health situation.
