Dr. Lisa Sanders is a rare find - a thin person with empathy and compassion for the overweight and obese. She's also an internist who specializes in researching and treating obesity, the author of the New York Times Sunday Magazine column " Diagnosis", and now an author of her own diet book - The Perfect Fit Diet .

Dr. Sanders describes her book as a refuge for those who have been beaten and defeated by the likes of Dr. Atkins, Dr. Dean Ornish, and countless other popular diets. As a clinician, she's seen and treated the refugees from these fads. And it's this treatment approach that she shares with the rest of us in her diet book.

Her premise is a sensible one. We are all individuals, not mass-produced robots. Just as we metabolize drugs differently, we metabolize foods differently. A diet that works well for one person won't necessarily work well for another. To complicate matters even further, food is much more than a source of nutrition for the vast majority of us. There are cultural and emotional undertones, not to mention taste preferences, to our food choices that make following any given diet for the rest of our lives difficult, at best. And that's the beauty of the Perfect Fit Diet. It takes all of these factors into consideration to style a diet that accommodates individual lifestyle, psychology, medical history, and food preferences.

That also is its drawback, however. For, unlike those block-buster diet books, which give the consumer a litany of do's and don'ts, this one requires work. Hard work. First, there's the assignment of keeping a one week food diary, a strict accounting of every morsel that passes the lips - the amount, the time of day, the setting, the degree of hunger, and the motivation for eating it. Not only is this time-consuming, but it requires a willingness to confront one's weaknesses head on. Such self-examination is crucial to any successful behavior modification, but it doesn't come easy to most of us.

And it isn't just food habits that must be documented and examined. Exercise habits and their intensity and duration need to be recorded, too. And not just planned exercise, but activities like walking down the stairs or around the corner to pick up a newspaper. That's a lot of documentation.

Then, there's the data gathering. If you haven't had your blood pressure taken, or your cholesterol or blood sugar checked lately, you'll need to have that done for this diet. If you have, but you don't have the results, then you need to get them. Again, the reason is a sensible one. A diabetic, for example, wouldn't do well on a high carbohydrate diet. A person with high cholesterol would do poorly on a high fat diet. Still, it doesn't make following this diet any easier to know that you have to go to the doctor to have the testing done in order to find your perfect fit.