Drinking water 30 minutes before main meals during a low calorie diet.
Water intake during a meal may have the same or similar effect.
Gastric emptying slows down as people age, which may be why water helps older people feel fuller for longer.
Overweight and obese middle-aged and older adults.
There is less evidence for benefit in younger people.
- Congestive heart failure
- Severely impaired renal function.
Any conditions where increased urine production may be problematic such as prostate conditions, incontinence, and immobility and difficulty getting to the toilet.
Water toxicity (hyponatraemia) is very rare in the general population. The typical victim is a marathon runner (unlikely to be overweight or obese).
Readily available and cheap.
Drinking 500ml water (2 cups) 30 minutes before each meal.
When combined with a hypocaloric diet, premeal water consumption leads to greater weight loss than a hypocaloric diet alone:
- approx. 2kg greater weight loss over 12 weeks
- 44% greater rate of weight loss.
Water is readily available and inexpensive. No studies have tested differences in tap, bottled, mineral or spring water.
Tips and challenges
- Although this is extremely easy, as with any weight loss behavioural change, long term motivation may be a problem.
- Older people are at risk of dehydration and this intervention may provide further benefit in this population.
- Where drinking water quality is inadequate, buying bottled water may be cost prohibitive.
NHMRC Level 2.