A thirsty business

Everywhere I look, people are drinking from bottles of water. At college, in shops, at home - what is it about bottled water that has become so addictive? Surely with thirst like this, they should be considering a check for diabetes. It seems I am not alone in seeing this behaviour as slightly odd.

"If you follow your thirst, you won't go wrong," says David Perlow, MD, an Atlanta urologist. He notes that pre-modern man never ran around sipping on a water bottle. "A dry mouth indicated it was time to run to the stream for a drink."

Over the last twenty years or so, we've been educated by the media that we must have our eight glasses a day... and for the last three months, Weight Watchers have been advising me to drink more fluids to ensure a healthy weight loss each week.

Perhaps it's my guilty conscience as I only drink a pint of water a day, approximately two pints of tea and another pint of pepsi max. So, I'm left wondering, am I doing it wrong? Will my weight loss increase with an intake of this clear elixir?

Boost Your Metabolism

Weight loss is primarily the result of our liver converting stored fat into usable energy. Does increasing your water intake improve a sluggish metabolism? Dr Donnica writes: "The Journal of Clinical Endocrinology and Metabolism (12/03/04) suggests that drinking sufficient water may actually increase the metabolic rate, or the rate at which people burn calories. While the researchers admit that the impact of their findings were small, this information could still potentially help with weight-control programs. In weight management, small daily improvements and behavioral changes can accrue for a significant long-term result. "

This German study involved reasearchers tracking caloric intake and energy expenditures among seven men and seven women who were healthy and not overweight. After drinking just over two glasses of water, subjects' metabolic rates increased by 30% for both men and women. The increases occurred within 10 minutes of water consumption and reached a maximum after about 30 to 40 minutes.

Dr Donnica notes: "Interestingly, the increase in metabolic rate differed in men and women. In men, burning more fat fueled the increase in metabolism, whereas in women, an increased breakdown of carbohydrates caused the increase in metabolism seen."

Researchers estimate that over the course of a year, those who simply increase their water intake by 1.5L a day without any other changes, will burn an extra 17,400 calories - five pounds. While further study into this is needed to confirm the findings, Dr Donnica notes: "Regardless of whether they are confirmed, drinking 8 to 10 glasses of water per day is an easy, harmless, and free first step for dieters."

Reduce your appetite

Maybe it's the appetite-quelling properties of water which cause this link. However, thirst and saiety expert Barbara Rolls, PhD points out that thirst and hunger are regulated by separate systems.

A study by Rolls and colleagues at Penn State University investigated whether people who drank water with lunch took in fewer calories than those who drank other low-calorie beverages. They discovered that drinking water had minimal effect on intake of calories at the meal.

"In all of our research, we have never been able to show that water can cause weight loss," says Rolls. She points out that the only way drinking water can assist weight loss is when it is a substitute it for higher-calorie beverages and foods.

Rolls, the author of The Volumetrics Eating Plan and The Volumetrics Weight Control Plan believes that eating high water content foods can aid dieters at feeling full. Rolls explains:"When you add water to a bowl of vegetables as in soup, the soup has greater satiety than when the vegetables are eaten alone with a glass of water, when water is incorporated into food or shakes, satiety is increased and subjects ultimately eat less food."

For the dieter, foods with high water contents can assist them to goal as: foods appear larger, higher food volume pleases orally and absorption of food is slowed, allowing you to feel fuller for longer.

A soon-to-be-published study by Rolls and colleagues shows that a high-volume eating plan resulted in more weight loss than a low-fat eating plan.

If you want to lose weight, Rolls recommends an eating plan that includes plenty of high-volume foods such as fruits, vegetables, broth-based soups, and oatmeal, along with adequate fluids to satisfy your thirst.