Dr's Casebook: Studies show drinking iced water may help you lose weight
Here is an old piece of advice – that you should drink more water if you want to lose weight.
Dr Keith Souter writes: It certainly seems to help people if they drink a couple of cups of water before meals.
You might think that it is simply a placebo effect.
But research does actually show that there is a very real effect and if you struggle with a weight loss diet, then drinking more water, especially iced water may make a difference.
This was the subject of a review of 11 studies on water intake and weight loss, which included more than 4,000 subjects.
Three of the studies showed that increased water intake among dieters led to greater weight loss.
Another study compared women who increased their water intake while they dieted, with those who kept their intake at a litre of water per day.
The women who had increased their intake had markedly greater weight loss.
Why drinking water should make a difference is not clear.
Indeed, there may be several reasons.
Firstly, water may quench the hunger, partly because a lot of people do not take enough water in any case and they may be mistaking hunger for thirst.
By quenching the thirst, they may also be quenching what they are misinterpreting as hunger.
Secondly, there could be a mechanical effect, in that the increase in fluid fills the stomach and makes the individual partially lose the appetite because of the full feeling.
Thirdly, there is a theory called water-induced thermogenesis.
This suggests that drinking water actually has an energy consuming effect.
That might sound hard to believe, but one scientific study published in the Journal of Clinical Endocrinology and Metabolism back in 2003 showed that drinking a half pint of water caused the metabolic rate to increase by 30 per cent.
It doesn’t last long, but it seems that it gives the metabolism a boost.
Further research found that the water had to be cooled with ice in order to produce the effect.
The body warms it up to body temperature and the boost to the metabolic rate is triggered.
Drinking warm water showed no boost to the metabolic rate.
The implication, of course, is to drink iced water to get the effect.