A randomised controlled trial published in 2009 involving overweight middle-aged and older adults showed that consuming 500mL of water 30 minutes before each meal resulted in 44% greater decline in weight loss over 12 weeks compared to a control group on a low calorie diet alone. This effect is likely due to a reduction in overall calorie intake. Additionally, stomach emptying slows down as people age, which may be why water helps older people feel fuller for longer.
Warning: Increasing water consumption may not be safe if you suffer from heart failure or severe kidney impairment.
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