Not Just Another Diet Monger : Entertaining Light: Healthy Company Menus With Great Style, <i> By Martha Rose Shulman (Bantam: $25; 465 pp.)</i>

Among the crew of officious diet-mongers filling our ears with what’s chic in science this week, Martha Rose Shulman is a class act. Her 1989 collection, “Mediterranean Light,” is about the only book of its kind that I’d be glad to cook from for purely non-dietary, everyday purposes. The secret of its excellence is that the author seems to be sharing a kind of pleasant, uncontrived cooking that she very much enjoys, not taking a scourge to food like some Savonarola of the kitchen.

The companion volume, “Entertaining Light,” has many of the same virtues. Again Shulman’s best weapon in keeping fat content on the modest side is just heading straight for dishes that need little surgery--their appeal never depended on fat in the first place. Thus there is a steady emphasis on uncomplicated fruit desserts (instead of pseudo-chocolate pseudo-mousse) and tons of interesting salads in no need of creamy dressings to make them palatable.

And--a point that can never be made too often or too loudly to would-be-fat-reducers--meat figures sparingly or not at all in this approach. Rather than fiddle around with ways to wrestle beef, veal, pork and lamb into schemes of salvation, Shulman leaves them out entirely. Grains, potatoes and sprightly vegetable combinations furnish the main thrust of many meals. Aside from a handful of recipes for chicken, rabbit and turkey, most animal protein comes from fish. All by itself this priority eliminates some painful culinary contortions and frees a recipe-writer to cook in a more natural, uninhibited spirit than we usually see in the genre.

Actually using “Entertaining Light” takes some perseverance, because the organization of the roughly 260 recipes is peculiar. Two chapters are devoted to complete menus for sit-down meals and buffets or informal gatherings (deliberately planned for widely varying numbers of people), three to the broad categories of hors d’oeuvre, salads and “dishes from the pantry,” while a few dozen more things go into a grab-bag chapter supposedly meant for “basic recipes.” Add an erratic index--none of the pastry recipes are listed under “Pastry” and individual menus aren’t listed at all--and the result is that much good material is difficult to find.

Given the attractiveness of the food, it’s more than worth putting up with the organization. One of the nicest things about recipes like Shulman’s dried apricot souffle, whipped cottage cheese with herbs made into a pasta sauce or grilled polenta unexpectedly paired with a green mole is that they suggest dozens of more ideas of the sort to a practiced cook (and may turn on some light bulbs for the less practiced too). You feel that you are being introduced not just to recipes but to a valuable way of thinking about food.

As in the previous book, the offerings I find most emblematic of the Shulman appeal are the many fish dishes (as rock-bottom simple as grilled tuna studded with garlic slivers, as elaborate as fish couscous ) and vegetable recipes--such as a soup of pureed potatoes and red peppers, a bitter chicory salad with walnuts, or hors d’oeuvres that use potato slices in lieu of crackers or bread to hold a choice of toppings. It’s also worth pointing out that here is one author who continues to use real cheese, not awful travesties, as a respectable part of “light” cooking, though she doesn’t exactly dole it out by the pound. Eggs too appear with regularity (sometimes with part of the yolks left out).

“Entertaining” books can be synthetic and stagy, but the menu emphasis in this one works very well. The lineups of courses convey much about Shulman’s individual taste and convictions--what a lot of agreeable, unpretentious little meals you can find here, and how nicely her menus clue in well-meaning seekers to the pleasures of vegetables as the keystone of a wiser diet. The wine suggestions are far more carefully built into the proceedings than in most menu cookbooks, with a real effort to find pleasant, drinkable, at least semi-affordable accompaniments to particular meals.

Though “Entertaining Light” may be far superior to other low-fat bibles, it strikes me as less successful than the Mediterranean book. This is because Shulman is working in a larger range of cooking styles while setting herself more programmacholesterol restrictions. At least some of the time. It certainly is not true that, as she says, “All the recipes are relatively low in calories, fat, sodium and cholesterol” (tapenade? pecan pie? whole-wheat pastry with ground almonds?) But there has been an effort to make the menus work out to a 1000 calorie per person, 30% of the calories from fat maximum. The results are honorable in the sense that good ingredients are used sanely and with some flair, but not everything has that lovely sureness of touch so evident in “Mediterranean Light.”

For my money, the author is best when she sticks to the Mediterranean. It’s a pleasure to share her pleasure in tomatoes, garlic, goat cheese, thyme, olives and figs. There are some well-chosen Mexican or sort-of-Mexican dishes in this book as well, such as tuna ceviche or a zucchini-avocado “salsa salad” (lime juice would be more convincing than the lemon juice and balsamic vinegar in the latter).

Shulman’s excursions to other regions are less successful. The handful of Oriental recipes feature East-West combinations that don’t bespeak a great feeling for Oriental originals. Nor would I go out of my way to make skim-milk versions of floating island, cheese souffle, Indian pudding or spoon bread--or put olive oil in this last. But to tangle with some standby of American and northern French cuisine in a low-fat manual is to take on more complicated decisions than Shulman had to in her first book.

At times I wonder whether the Paris-based author has a clear idea of American shoppers setting out to find ingredients. Brill is not a fish found on this side of the Atlantic; the description “giant white beans--fava beans” may sorely puzzle someone wandering around an ethnic market; the pink-fleshed fish Shulman calls sea trout is usually known as salmon trout over here, where “sea trout” refers to another fish.

Some caveats should also be registered on the nutritional approach. In aiming for more defined fat limits than in “Mediterranean Light,” Shulman also unfortunately comes closer to the naive numerical game-playing of many diet books. The recipe for a quickie appetizer of store-bought tortellini primly says “122 calories” per portion, but portioning out four of the tiny things per guest won’t secure you a reputation for liberality to the hungry. Readers who aren’t keeping their eyes open may automatically use the standard “large” eggs rather than the “medium” ones (three ounces less weight per dozen) called for in most of the recipes. The switch, to which the author does not draw attention, is a neat way to make the fat and cholesterol tallies come out a bit more respectably.

Furthermore, it is arithmetically impossible for the hard-boiled eggs with a garlic-anchovy-caper filling to work out to the two milligrams of cholesterol per serving claimed in the nutritional data (the right figure must be more than 250), and from a glance at the ingredients there is no rhyme or reason to some of the stated variations in sodium content among a bunch of vinaigrette recipes. It’s an ill-kept secret that the tallies proudly billed as “complete nutritional breakdowns” in health-minded cookbooks can be both arbitrary and astonishingly inaccurate.

In a way it’s a pity Shulman didn’t bite off something closer to the aims of “Mediterranean Light,” but to look at it another way, her intelligence and good culinary instincts soften the artificiality a lot. More glitch-ridden and perhaps spread thinner than its predecessor, her new book still manages to steer people concerned about diet in fruitful directions.