How to write a diet book: looking for some extra income? Always wanted to see your name in print? Writing a diet book is easier than you think. Don't worry if you have no expertise or degree. You've been eating all your life, haven't you?

Step 1. Choose a Title

The inside can always rehash some recent (or not so recent) diet theory, maybe with a new twist. But the title has to grab the reader's attention. Some guidelines:

* Trendy place. Consider naming your diet after a well-known, attractive destination like South Beach, Beverly Hills, Scarsdale, or the currently popular Sonoma.

* Magic bullet. Make up a diet that will banish unwanted fat forever. Ultra-Metabolism, for example, "ignites the natural fat-burning furnace that lies dormant within us."

* Personalize. People love diets that are tailored to them. Eat Right 4 Your Type has done gangbusters by recommending diets according to blood type. The Zone and The Carbohydrate Addict's Diet have people answer questionnaires to find the diet they need.

* Single body part. Zero in on something (The Abs Diet, The Cellulite Breakthrough, The Butt Book) that people would rather not display at the beach this summer.

* Single food. Other than The Rice Diet, these aren't currently in vogue. But many of us are old enough to remember The Grapefruit Diet and The Cabbage Soup Diet. (The Pizza Diet, The Latte Diet, and The Tiramisu Diet are still up for grabs.)

* Single nutrient. Low-fat (high-carb) and low-carb (high-fat) diets are both passe right now. But don't worry. If you wait a few years, a new generation of dieters will again be ready to blame their unwanted flesh on carbs or fats. (Note: Don't try to blame only bad fats or carbs. That idea's already been taken.)

Step 2. Make Promises

Weave at least 5 of the following 10 promises into the opening chapters. (If you have trouble, relax. Any decent diet-book publisher has staff that can do it with their eyes closed.)

1. You won't feel hungry on this diet.

2. This diet is for you if you've failed on other diets.

3. You won't just lose weight, you'll have more energy, you'll be healthier, and you'll show no signs of aging.

4. You don't have to give up your favorite foods.

5. You don't have to count calories, fats, carbs, or anything else.

6. Your weight loss will last a lifetime.

7. Lose -- pounds in -- weeks!

8. This diet will detoxify your body.

9. You'll enjoy a delicious variety of mouthwatering foods.

10. This diet is backed by reams of scientific research. (To boost sales, accuse the scientific establishment of completely ignoring the research.)

Step 3. Keep it Simple (or Complicated)

The book jacket will call the diet "simple" no matter what. But you need to choose one of two audiences.

* Nonreaders. The Fat Smash Diet and Good Carbs, Bad Carbs are perfect examples of diet books for people who don't like to read. If that's your target, after the first couple of (very short) chapters, fill up your pages with:

** lists of foods to eat or avoid;

** recipes (leave lots of blank space);

** blank (or lined) pages where people can write ("what was easy in phase 1" or "what I ate today");

** charts (lists of fiber, calories, fat, or carbs in foods, a body mass index chart, calories used by different exercises, etc.).

* Science lovers. Books like Ultra-Metabolism and The Zone are aimed at people who are impressed by scientific evidence, especially if it has been ignored. If that's your target, deluge them with:

** scientific names (lipoprotein lipase, cortisol, leptin, resistin, adipocytes, mitochondria, etc.);

** explanations of how the diet can prevent all or (if the publisher's lawyer is nosing around) most diseases;

** references that fill up the final 50 or so pages. (Don't worry. No one will check to see if the studies back up your claims. Many references in The Shangri-La Diet are simply testimonials.);

** lists of supplements (herbs, vitamins, enzymes) to take. They often appeal to people who like hidden scientific evidence.

Step 4. Think Outside the Box

Feeling overwhelmed? Does it seem like all the good ideas have been taken? Put down that piece of cheesecake and hit the word processor. As long as Americans are chubby, there's a market for diet books.

Go beyond what's been done. (Don't forget to spend a chapter or two trashing your competitors.) Find a way to tailor your diet to your readers' genes or hair color or left- or right-handedness or left-or right-brainedness.

Tie stress or inflammation to obesity. What about a diet for postmenopausal women? Toxins are getting a lot of play, but the idea still has legs. Surely you can find something to blame for those extra pounds--pesticides, hormones in milk or beef, food dyes, mercury in fish, allergies.

Think of it as that creative writing course you never took.