RESTAURANT REVIEW : Looking for a Low-Cal Locale : * Considering the dietary restrictions at Thin’s In, its menu is impressively large and eclectic.

You see them the second you hit the door, the massive mounds of lemon-colored, chocolate-brown and other multicolored fluff jammed into a huge dessert case. Atop the case, cookies fill enormous metal trays. Welcome to Thin’s In Cafe, a rather plain but breezy Tarzana restaurant and desserterie that caters to people seriously watching their diets. Believe it or not, all the indulgent-looking meals here are portion-controlled and sanctioned by the American Heart Assn.

It’s not exactly a luxury restaurant, but it is reasonably comfortable. The booths, lined up against one wall, are nicely padded. The best tables are up on a semiprivate wood-paneled mezzanine, away from the madding crowd below. (But notice how the salmon-colored napkins and bright green paper place mats clash with the blue packets of Equal and pink packets of Sweet ‘N Low in the sugar bowls. Kvetch, kvetch.)

Considering Thin’s In’s dietary restrictions, I’d call the menu impressively large and eclectic. All non-dessert items, whether they be salads, charbroiled sandwiches, pizzas or entrees, are listed according to the number of protein, bread, vegetable or fruit exchanges (if you’re on a diet, you know what exchanges are; if you’re not, don’t worry) conforming to American Heart Assn. and Weight Watchers standards.

Don’t ask about the number of calories, though. One of the waitresses informed me that listing calories is dicey, since a regulation she didn’t elaborate on demands that the count be within 3% of the exact number of calories a dish contains. Apparently, that’s too much trouble for the kitchen to reckon with.

Soups, such as the flavorful split pea and the tomato Florentine, make good starters here. The dinner salads, made with thick low-cal dressings (for example, an unctuous green goddess thickened with nonfat milk), have a pleasant freshness.

Hot lunch entrees are served at all hours and run to things like egg rolls, chicken pot pie and flame-broiled turkey burgers on special buns.

I like the pot pie, with its thick yellow gravy, chunks of white chicken meat and a rich-tasting crust made with diet margarine, and I find it difficult to believe that this isn’t a diet-breaker.

The egg rolls, I must say, are downright weird, with a “skin” resembling another crust. They’re filled with carrot and minced chicken, then smothered in your choice of a dull brown sauce or a bizarre, sugarless apricot puree.

The dinner menu is more ambitious, and some of the dinner dishes do not seem to belong on a diet-themed menu. Maybe they don’t. When I asked the cashier about calories in the Belgian brisket, for instance, he replied: “Beef is not the best food for a diet, so figure a six-ounce portion at about 90 calories an ounce.” He neglected to mention that this meat is blanketed in a thick tomato gravy.

The dishes are all tasty, though. The brisket is soft and meltingly tender. The barbecue ribs are good, tender meat with a sweet tomato-based sauce. The sweet-and-sour cabbage rolls are not unlike those you’d fine in almost any Eastern European, Jewish-style restaurant, though the stuffing is leaner, being made from lean veal. Veal sausage and peppers--a very low-fat sausage sizzled up with green bell pepper--is served over pasta.

One of the best innovations is something called hot air fries, which come with most entrees. They’re made in a contraption called a RAIR fryer (“Rotating AIR”) from real potatoes, waffle cut. Being cooked in hot air, they contain no oil. They brown up surprisingly well, nicely crisp around the edges, and taste pretty good all by themselves. Still, everyone here eats them with judicious amounts of flavorings, such as barbecue sauce (a diet version) and (dare I say it?) salt.

The real raison d’etre for Thin’s In seems to be the sumptuous-looking desserts, which appear on practically every table in the place. “Desserts without guilt” they’re called--huge things, billowy with mountains of froth that give the impression of carefree richness. That’s not real whipped cream, though, but a sort of trompe l’oeil whipped cream fashioned from nonfat milk, NutraSweet and emulsifiers.

The banana split would fool almost anybody, though it’s made with a fructose-sweetened soft-serve ice “cream” and “whipped cream,” as well as bananas and raspberries. Peanut butter cheesecake employs a low-fat ricotta but tastes a bit chalky to me. The mountainous fruit shortcake is two huge layers of eggy sponge cake filled with “whipped cream” and sugar-free blueberry preserves.

As for the chocoholic pie--well, you’d better go and see for yourself. The very name makes me squirm with denial.

WHERE AND WHEN

Location: Thin’s In Cafe, 18706 Ventura Blvd., Tarzana.

Suggested Dishes: Chicken pot pie, $6.25; barbecue combo, $10.95; Belgian brisket, $11.95; banana split, $4.25; chocoholic pie, $3.95.

Hours: Lunch and dinner, 11 a.m. to 9 p.m. Mondays through Thursdays, 11 a.m. to 10 p.m. Fridays, 11 a.m. to 11 p.m. Saturdays, noon to 9 p.m. Sundays.

Price: Dinner for two, $18 to $35. No alcoholic beverages. Parking lot in rear. Discover, MasterCard and Visa cards accepted.

Call: (818) 776-0229.