Would you like a piece... of water?

FOR Dr. Melissa Hershberg, water isn't just something she drinks -- it's something she eats.

The Winnipeg-born, Toronto-based physician has revealed her secret in her new book, The Hershberg Diet: Discover How the Fourth Macro Can Help You Shed Pounds and Beat the Metabolic Syndrome.

The hardcover hit Canadian bookshelves earlier this month. It's expected to be picked up in the United Kingdom in the fall -- and in the United States next year.

In a market flooded with piles of diet books urging people to eat low-fat and high-carb, low-carb and high-protein, high-fat and no-carb -- or some combination of the above -- Hershberg's angle is unusually simple.

"People know about drinking seven glasses a day of water. But it's not about that. It's about eating water," explains Hershberg, 29, during a phone interview from her Toronto home.

"It's not inherent to think about eating water."

Eating H20 may evoke toothache-inducing images of crunching on blocks of ice. But that's not what Hershberg means.

She wants people to nosh on food with a high water content. Think juicy "real food" items such as fresh fruit, vegetables, low-fat dairy and meat.

These water-packed goodies contribute to a feeling of fullness and have the added bonus of containing the calorie-free component of water.

Followers of her diet can lose 10 pounds in two weeks, she says.

Plus Hershberg believes her diet can help stave off and even reverse metabolic syndrome, a cluster of conditions -- high blood pressure, high blood sugar, high cholesterol and abdominal obesity -- that can lead to cardiovascular disease.

Hershberg, who grew up in Tuxedo, explains it simply: Eat a handful of grapes and you get a decent amount of food for relatively few calories. Eat a handful of raisins -- the same fruit with its water removed -- and you consume double the amount of calories and sugar, but feel less satisfied.

The same goes for foods such as crackers and pretzels.

"Those foods are healthy, but they are also dry. So every bite that you put into your mouth is a calorie. People can just eat tonnes of calories and it doesn't fill their stomach up because there's no water," says Hershberg.

The former Winnipegger -- who now works out of the cutting-edge Toronto Clinic -- considers water-packed foods to be nutritional powerhouses. In fact, she calls water the "fourth macronutrient," or the "fourth macro," the term mentioned in her book title. Conventional thinking pegs carbohydrate, protein and fat as the three macronutrients -- the three main components of food. But water, she says, is often overlooked.

How can a calorie-free, vitamin-free substance be a nutrient?

"It depends on your definition of nutritious. To me, something that's nutritious means something that's good for you," says Hershberg, who notes that more than half of the human body is made of water.

"Foods that are nutritious are the ones that have high water content."

One of her goals is to win over fruit-phobics, mostly followers of the Atkins Diet, which advocates eliminating most fruits from your menu due to their sugar content.

She says that even though many fruits contain moderate amounts of sugar, it is absorbed slowly because of the fruit's fibre. That makes it is less likely to spike insulin levels and lead to weight gain.

"What really shocks me is the amount of confusion that is out there," says Hershberg, who recently had a "bright, educated" patient in her office who was completely confused about what to eat. She's one of many of Hershberg's patients who are overwhelmed by the diet information floating around in books, on the Internet and in the news media.

"She heard that cantaloupe is just terrible for you... I thought to myself, 'What is going on?'"

"I explained to her what would happen if you left that cantaloupe on your porch for a couple of years. It would shrink down to nothing. That's because the majority of the cantaloupe is made from water.

"If the majority is water, how could it be so bad for you?"

Hershberg's revelations about water came to her during a medical school assignment about food labels. Upon close examination, she realized that while labels listed the carbohydrate, fat and protein content of foods, the numbers didn't add up.

Something was being left off the labels. Then it dawned on her: Water.

"All of a sudden I looked at my husband and thought, 'Oh my God, I am going to write a book," exclaims Hershberg, who graduated from medical school in 2004.

She studied at McGill and the University of Toronto.

Hershberg got her book proposal on paper in about a month while completing her medical residency in Toronto.

Publishers liked her ideas, but questioned her experience.

"A lot of them were nervous because here I am -- a young, fresh girl who doesn't have much of a... profile.

"I'm not wise and grey. I haven't been around. But I know what I know," says Hershberg, who landed a book deal with Key Porter Books after only a few months of shopping around for publishers.

Hershberg's knowledge of nutrition stems from her teenage years.

Hershberg -- whose maiden name is Yan -- was just 15 when she stopped eating.

It started when the competitive gymnast and St. John's-Ravenscourt student suddenly packed on about 15 pounds after a serious knee injury forced her to hang up her bodysuit.

The formerly active and slender teen -- who was used to eating all she wanted without worrying about her waist size -- resorted to drastic means to get back to her former self.

"I didn't know what to do," says Hershberg. "I just didn't eat. Obviously, I lost weight. But it was awful."

The experience was brief but life-changing, fuelling her more-than-decade-long quest for nutrition knowledge and passion for healthy eating.

Another catalyst for writing her book is knowledge that most physicians don't know a lot about nutrition.

"(Doctors) have to know a little bit about everything. We're expected to council patients on nutrition, and yet we're not taught nutrition in school. It's not part of our medical training.

"We're just given the Canada Food Guide and told that this is what to use."

Hershberg hopes that her easy-to-read book can serve as a resource for physicians who want to learn how to help patients lose weight.

Her concepts are easy to understand, including the idea that people should eat more "hottie" items -- thermogenic foods that naturally burn a few calories when metabolized.

The Hershberg Diet does not make its followers count daily calorie intake, though junk food is "budgeted."

The book also contains recipes from some of her favourite Toronto restaurants. Also included are recipes she invented after testing her kitchen experiments on her husband, Tyler.

Hershberg credits many of today's popular diets with having some useful information.

Even the much maligned butter and bacon-touting Atkins Diet has validity, says Hershberg.

Earlier in the month, the Atkins Diet gained headlines for after a research trial in which subjects lost more weight and reduced cholesterol levels further than other more higher-carbohydrate diets.

Hershberg is adamant that her book takes the best out of each of the top diets -- and adds her unique twist.

"I think there's a lot of value in the book," says the doctor, whose mother, Pamela follows the Hershberg diet. Her father Gary, a dentist, has been slower to adopt the regimen, she jokes.

"What diet works for one person isn't going to work for the next person. You need a choice."

Key points in the Hershberg Diet:

* High-water foods (fruits, vegetables, lean meat and low fat dairy) are more filling and more nutritious than "dry" foods.

* Water is the "fourth macronutrient" that can help shed pounds and stave off metabolic syndrome -- abdominal obesity, high blood pressure and high cholesterol.

* While many "dry" foods such as whole wheat bread and crackers are healthy, they don't keep you as full as more juicy foods.

* Dieters shouldn't be afraid of the sugar in fruit; most fruit is high in fibre, which slows the absorption of sugar in the bloodstream.

* Dried fruit contains about double the sugar and calories of fresh fruit. Such concentrated and water-less food is excellent for high-performance athletes, but not for average, moderately active people.

* Excess insulin is largely responsible for metabolic syndrome, a set of conditions that can lead to cardiovascular disease. Consuming fast-acting carbohydrates causes insulin spikes in the blood.

* "Hottie" foods heat up the body and help burn extra calories. Protein is the most "hottie" food, followed by carbohydrates and then fats.

* Skipping meals slows the metabolism and leads to weight gain.