Instructions: Fill a drinking glass with ice water. Let it sit. Then empty it out, and pour boiling water into it. Chances are it will crack.

Now, consider that glass your body. The jarring results of that experiment are what happens when too many foods of one extreme or another end up in your body.

Thats how Alexander Ong explains the importance of achieving balance - proper yin and yang - in food.

As former chef of Xanadu in Berkeley, which closed last year, Ong created an entire menu based on yin and yang. Now he plans to introduce some of those Asian dishes at Betelnut Pejiu Wu in San Francisco as executive chef.

His friend Jeffrey Powell, chef de cuisine at Plumpjack Squaw Valley, will do the same, offering his Mediterranean twist on yin-yang for a special spring menu.

With balanced food, the flavors are just better, and it digests better, says Powell, who started studying yin and yang principles after his wife, Sal Powell, quit her job as a stockbroker and opened a feng shui consulting company.

Opposite forces

Dark yin and light yang are the oppositional balancing forces behind Chinese philosophy and feng shui, the art of arranging the environment to foster peace and happiness.

In Chinese medicine, people who are more yin tend to be easily cold and tired. People who are more yang tend to overheat and be full of nervous energy.

For better health, yin people are advised to eat more yang foods - generally hot, dry and spicy; while yang people should eat more yin foods - generally cool, moist and salty.

Red meat, coffee, chocolate, ginger, butter, shrimp, most spices and red wine are considered yang. Eggs, cucumbers, chicken, mangoes, apples, oranges, ice cream, water and champagne are yin. And pork, sweet potatoes, chestnuts, rice, figs, carrots, honey and chardonnay are neutral.

Applying feng shui to food isnt simple. Each person is thought to possess a unique combination of five elements, with one dominant: fire (people who love excitement and success, and are often stressed), wood (physically active, quick and decisive), water (emotionally reserved and imaginative), metal (those who are organized and like to be in control), and earth (social people who enjoy good food and entertainment).

For the greatest health and success, experts say, it is important to eat a balance of foods associated with the five elements and with yin and yang.

Complications

That can get complicated. For instance, lamb, which is yang, is considered fire although beef, which also is yang, is considered earth. And while chicken is yin and wood, free-range chicken is yang and metal. If all this leaves you feeling a bit unbalanced, here are some easy feng shui tips from experts:

o Opt for fresh foods over processed foods, which contain chemicals believed to block energy.

o Avoid meat thats been frozen too long, vegetables past their prime and any food past its sell-by date because it has lost its energy and will leave you feeling sluggish.

o Avoid too many frozen foods, even if reheated, because they will weaken your energy.

o After using a food processor, mixer or blender, let food rest for several minutes to settle agitated energy.

o Most important, if youre in a bad mood, dont cook.

Just go out to eat instead, Sal Powell says. Or else your bad energy will go into your food.

Just be sure the chef at the restaurant is in a better mood.

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