"Drink lots of water" has always been standard diet advice. I thought the reason was simply kilojoule/Calorie subtraction - replace soft drink, juice or alcohol with water and you save kilojoules. And it can be a considerable saving. Drink 600ml water in place of a 600ml Coke ‘buddy' (now the most popular single serve size at supermarkets) and you cut back on 1080 kilojoules (258 calories).
Water drinkers eat less
There's also a belief that drinking water distends your stomach, reduces sensations of hunger and leaves you feeling fuller, all desirable feelings when you're on a diet. There's some research to back this up. US researchers reported that kilojoule intake among habitual water drinkers is approximately 9 per cent less (81 kilojoules or 19 calories a day) than those who do not drink water.
New study confirms water's weight loss advantages
All this has been confirmed in a 2008 study (from Virginia Tech in the US with funding from the Institute for Public Health and Water Research) which tested the "drink-water-before-your-meal" idea on overweight people. The scientists discovered that the subjects ate 13 per cent less after the water. It didn't matter what their age, weight or sex was, nor whether they regularly drank water or not.
More water, fewer kilojoules
Twenty-four overweight and obese older adults aged 55 to 75 took part in this experiment. They came in for a breakfast on two occasions - once with nothing before, then the second time they drank 2 cups (500ml) chilled, bottled water first. What they ate was covertly weighed and measured. Participants consumed significantly less after the water pre-load. This represented a drop of 222 kilojoules for the men and 765 kilojoules for the women. The researchers think the water works by slowing the rate of emptying of the stomach and promoting fullness.
Cheap and effective weight control strategy
Considering that over half of Australian adults and 25% of Australian kids are now overweight or obese, pre-meal water can be a simple inexpensive and effective weight control strategy.
New strategy helps you stay hydrated
It's also desirable because most of us fail to drink enough water over a day. A 2007 survey conducted by Brita Water Filters found that 3 out of 10 Australians say they drink three glasses of water or less a day, significantly less than the recommended daily intake.
So here's to our new healthy weight loss mantra: "Drink plenty of water before you start eating". Cheers!
Another study re-confirms that water helps
Scientists report results of a new US clinical trial confirming that just two 250ml/8-ounce glasses of the stuff, drunk before each meal, enables people to shed kilos. It's a simple method of appetite control. Read more detail here.
Reference quoted: Davy BM, Dennis EA, Dengo L, Wilson KL, Davy KP. Water consumption Reduces Energy Intake at a Breakfast Meal in Obese Older Adults. JADA 2008; 108: 1236-1239. View the paper here.