I didn't need to carry around a plastic bag filled with spinach leaves. I just needed to surround myself with understanding friends to get me through two weeks of Scarsdale dieting, most of it in restaurants.

Finally carving out two weeks when I could diet after heavy eating for the Fall Dining Guide, I chose the Scarsdale diet as one that reputedly melted off weight quickly, would leave me full enough to be able to write about food, and had my doctor's approval. The Scarsdale diet is a high-protein, low-carbohydrate diet with a specific menu each day and a heavy emphasis on high-protein bread, grapefruit and spinach as well as other raw fruits and vegetables. (Details of the diet are spelled out in The Complete Scarsdale Medical Diet , by Dr. Herman Tarnower and Samm Sinclair Baker, $7.95 at bookstores.)

I never found the diet's required protein bread in a restaurant, and investigating rumors of menus that featured the diet turned up only Hecht's -- which was phasing it out -- and Health's-A-Poppin, which followed it just intermittently. But I did learn that if you choose your restaurants carefully, sometimes calling ahead to check their menus, you could diet in restaurants -- sometimes pleasurably, sometimes cheaply. It required, however, not only firmness of purpose, but a firmness with waiters to persuade them to comply with your order.

Along the way, as I lost pounds, I developed dieters' peeves:

When it is 1:30 p.m. and I have had nothing all day but grapefruit and a slice of toast, I have no patience with a restaurant that refuses to leave off the potatoes or gravy or that will not substitute lettuce salad for coleslaw.

It is pure greed that drives a restaurant to charge for parts of meals that are not served, such as the 70-cent portion of frozen yogurt I asked to have left off my fruit plate. The phrase no substitutions is a red flag. There is no good reason a restaurant cannot exchange french fries for a few leaves of lettuce or spinach if there are some in the kitchen.

I know my diet, and a waiter is wasting effort trying to convince me that tuna salad with mayonnaise is low-calorie. Even more exasperating, though, are the cottage cheese pushers. Some restaurateurs seem to believe that if you add cottage cheese to a platter it reduces the calories. Thus, the Eatery at White Flint serves a Diet Delight of hamburger without the bun, instead served with cottage cheese, tomatoes and half a canned peach; the bun has fewer calories than its substitutions.

It is frustrating to explain carefully that you want your salad without dressing, only to have to repeatedly send it back because it comes with dressing. You have to remember that the guilt is theirs, not yours, and stick to your request. Dieting is easier is you ask the kitchen to leave off the rice or potatoes, but if they arrive anyway, transfer them immediately to another plate and ask the waiter to remove them, along with the bread.

The Scarsdale diet requires particular meals each day, so I have organized my discoveries by that scheme. What I discovered, however, can be applied to many different kinds of diets. It is the restaurant's flexibility, attitude and type of menu that are crucial.

It is common knowledge that dieters are obsessive and self-centered. We beg whatever indulgences our companions will contend with. Thus, in true dieter's fashion, I am going to talk about my diet, at least for two weeks, one column for each week I deprived myself of pastas and cream sauces and wine and buttery pastry crusts and all those tasty fringe benefits of my job.