Accustomed to diet breakfasts of grapefruit and toast, we were soon forking down blueberry pancakes, french toast, custom-cooked eggs, broiled rainbow trout--and even a shot of Amaretto in our coffee on cold mornings.

For the next eight days on the 225-mile trip through the canyon there would be no telephones, no clocks, no news from any source. But we would have something else--calories without guilt. Thousands of them. All we could eat, for they would be burned off so fast they would never have a chance to settle comfortably on our revved-up bodies.

This we learned at lunch soon after we entered the river and experienced our first white-knuckled sloshing in a rapid. We survived! This was no time for yogurt and carrot sticks. This was Miller time, and time to build the largest sandwich our chattering teeth and quivering fingers could manage.

Fear, we discovered, burns a lot of calories. So does exhilaration, which soon replaced fear.

Our days were spent winding down this beautiful staircase of a river enclosed in brilliant canyon walls. We alternately hurtled through roaring rapids and then baked dry in a broiling desert sun. We scrambled up sheer rock walls, hiked into remote side canyons to swim in limpid pools or shower under a crashing waterfall. Or we simply drifted through geological history that took us back through 2 billion years.

By sunset we were exhausted and famished. As soon as the two rafts were secured, those same river guides who had been navigating the rapids all day jumped into a new role--they became the expedition chefs.

It wasn't long after we had unloaded the boats and collapsed on our cots that heavenly aromas began to drift through the canyon. Derryl Diamond, lead pilot, unsnapped the leather sheath on his belt, took out a pair of pliers, used it to lift the hot lid from a dutch oven to check the cake he was baking.

A cake? A mile deep in the Grand Canyon?

He used a mix, he confessed. No matter. You simply can't criticize a mix when a cake is being baked by a barefooted, bronzed river pilot on a remote beach in the wilderness. Just the idea of a cake is delicious.

Our camp kitchen was simple but efficient. We traveled with two charcoal grills, a griddle, two table-top propane stoves (five burners total), three cast-aluminum dutch ovens, several steel buckets, two tables with pipe legs and a wonderful blackened coffee pot.

Food for 31 people (five were crew) for eight days was packed in waterproof cans and ice-cooled insulated compartments in a steel frame in the rear half of the rafts.

This packing job is usually meticulous, but not always. Diamond remembers the time they were on their way and discovered they had left the bread behind. There is no turning back in the canyon, but they were able to send a message at Phantom Ranch, a campground midway on the trip. An airplane flew through the canyon and made an air drop. "That box of bread skipped across the river like a stone," laughed Diamond.

There are no dieters in the canyon, just as there are no atheists in the face of some of the more awesome rapids. Dinnertime was wonderful. We plunged into beautifully broiled steaks, charcoal-grilled pork chops with Spanish rice, a marvelous stew with biscuits, barbecued chicken breasts with corn bread. We didn't skip the biscuits, cut the fat from our steaks nor strip the skin from the chicken. We had earned every calorie, including dessert every night. We even had homemade strawberry ice cream, hand-cranked by two brawny boatmen aboard the raft.

Not all river outfitters operate alike. They develop their own systems for rigging their pontoon rafts and feeding their passengers. One outfitter served wine every evening with dinner. I wondered where they put down the glasses; we always perched on rocks or sat cross-legged on the sand, with our plates on our laps. Another river outfit carried alfalfa sprouts for the salad bowl.

Nearly all carry beer (except a Mormon company). We had 50 cases, chilled as needed in mesh bags which floated behind the rafts, bouncing through the 52-degree rapids, knocking the paint from the labels. For a group of British passengers, our outfitter had stocked the beer bags with Guinness Stout and Bass Ale.

While dinner was usually a rapturous highlight, there have been exceptions. The river guides still talk about the time that one of the big rafts carrying a dozen passengers struck a huge boulder in the middle of Crystal Rapid--one of the most famous in the canyon. The ends of the raft bent around the rock, where it was pinned by the current. Passengers scrambled to the upper pontoon and learned the bad news. They had hit the rock at low water level and would have to wait for the daily release from Glen Canyon dam, 112 miles upstream. The boatmen fished a box of food out of the water and served dinner in the middle of the rapids. They were freed by rising water the next morning.

Our river menu even included the local rainbow trout. One of the passengers caught his limit (two), using a collapsible fishing rod, with cheddar cheese for bait. The pilots covered them with orange slices, sprinkled on Italian herbs, chopped onion and butter, wrapped them in foil and broiled them over charcoal for breakfast. Superb. And everyone was surprised to discover the canyon trout had flesh the color of canned red salmon and a subtle salmon flavor.

It wasn't long before our group of strangers became a team. We had even rescued one of our own. Kathryn, the chemist from Philadelphia, had been lost overboard in Horn Creek rapid. She was in front of me one moment, and when the wave swept over, only one tennis shoe remained.

"Man overboard!" we were taught to yell. This was quickly amended to "Person overboard!" and this was refined to "Female unit overboard!" We scooped her up unharmed downstream.

We celebrated her heroism at dinner, sharing booze from our plastic flasks and toasting the adventure with cocktails in our plastic coffee cups.

Most of us had come on the trip new to both white-water rafting and to camping. We were now converts to the outdoors and fanatical about preserving the beauty and serenity that surrounded us.

Our boat left no trace in the water, and we left no trace at our campsites. Even the sand was sifted with toes to detect any stray cigarette butts. We took turns with the sledgehammer, smashing flat the beverage and food cans so they would compact in our trash. We had made the acquaintance of "Oscar," the portable toilet, and even the human waste was carried back out of the canyon.

We detoured our raft to scoop up any stray beer cans that were lost overboard in the rapids.

On our last star-studded evening a farewell speech by our leader admonished us: "Go back out into the world and treat it the way you did the canyon this week."

Home again, reacquainted with reality. We have fresh vegetables and fresh milk, which we missed in the canyon, but have reluctantly renewed our Falls Church routine. Back to grapefruit and toast.

LAVA FALLS BEEF STEW (30 servings)

Named for the most awesome rapids on the Colorado River, this stew has for its starting point a can of beef stew. Like much camp cooking, this is not a recipe kind of cooking. You use what you have on hand. Oil for dutch oven 2 large onions, chopped 4 pounds pre-cooked stew meat cubes (We used eight leftover strip steaks) 6 1/2-pound can beef stew (We used Chef Mate, a Carnation product) 2 28-ounce cans whole tomatoes 3 8-ounce cans tomato sauce 2 4-ounce cans green chilies, chopped 2 16-ounce cans zucchini 2 8-ounce cans mushrooms 4-ounce can chopped ripe olives 2 24-ounce cans tomato-vegetable juice 4 potatoes, cooked and cubed 1/2 pound cheddar cheese, grated 2 tablespoons hot pepper sauce 1/2 cup worcestershire sauce Salt and pepper

Oil a 16-inch dutch oven and preheat over hot charcoal briquets. Saute' chopped onions until soft. Brown meat, if necessary. Add remaining ingredients and heat thoroughly. Recipe by Derryl Diamond of Diamond River Adventures, Page, Ariz.

DUTCH OVEN PINEAPPLE UPSIDE DOWN CAKE (30 servings)

Commercial mixes are a tremendous help to camp cooks. There is even something about outdoor appetites that helps transcend a humble beginning in a cardboard box. 2 18.5-ounce boxes white or yellow cake mix 3 13-ounce cans pineapple chunks, drained; reserve juice 8-ounce jar maraschino cherries 1 cup brown sugar

Mix cake batter according to directions, but substitute pineapple juice for water in the recipe.

Line with waxed paper a 16-inch dutch oven, camp style, with short stubby legs and flat lid. Spread the pineapple chunks, cherries and brown sugar in the dutch oven. Pour cake batter over the fruit/sugar layer.

Spread aluminum foil on the ground and arrange a single layer of hot charcoal briquets in a pattern to fit under the dutch oven. About 12 coals two inches apart should do it. Place the dutch oven over these coals. Cover, add more coals to the lid, about 9 evenly distributed.

When you begin to smell the aroma of the cake, check it by lifting the lid carefully. When the bottom of the cake is cooked, the cake will draw away from the side of the pan. When this happens, remove the oven from the coals and add the coals that were below to the coals on the lid. It usually takes about 45 minutes for the cake to cook. You may need to replace dying coals with hot coals from time to time. Recipe by Derryl Diamond

BLUEBERRY PANCAKES (6 servings) 2 cups flour 1 teaspoon salt 1 tablespoon sugar 3 teaspoons baking powder 2 eggs, well beaten 1 1/3 cups milk 3 tablespoons butter, melted 1 cup fresh blueberries, washed

Sift together dry ingredients. Combine eggs and milk. Add to dry mixture and beat only until smooth. Stir in melted butter and blueberries. (If canned blueberries are used, drain thoroughly and blend in carefully so they won't disintegrate.) Bake on lightly greased hot griddle, turning when bubbles appear on the surface and each side is golden brown.

CANYON CORN BREAD (8 to 10 servings) 4 slices bacon, cooked, crumbled; reserve fat 4 eggs 1/3 cup bacon fat or salad oil 1 cup sour cream 8-ounce can creamed corn 4-ounce can green chilies, chopped, drained 1/4 teaspoon baking soda 8-ounce package buttermilk corn bread mix

Fry bacon in 9- or 10-inch iron frying pan. Pour off fat, leaving pan greased with bacon fat. Crumble bacon and set aside.

Mix together eggs, 1/3 cup of the bacon fat or oil, sour cream, corn and chilies. Add baking soda to dry corn bread mix. Add dry mixture to wet mixture and stir until well blended. Pour batter into heated, greased frying pan. Sprinkle crumbled bacon on top. Bake in 450-degree oven for 30 minutes or until golden brown and firm in the center. This makes a dense, very moist corn bread.

For cooking the corn bread when camping, the dutch oven should be placed on a circle of hot charcoal briquettes with more briquettes placed on the lid of the dutch oven. The corn bread will bake in about 30 to 40 minutes.

CARAMEL PEACH CRUNCH (8 servings) 1 cup flour 1 3/4 cup uncooked, rolled oats 1 1/2 cups brown sugar 1 teaspoon cinnamon 1 teaspoon salt 1 cup butter or margarine, melted 2 29-ounce cans sliced peaches, drained

Line a dutch oven with aluminum foil and preheat over coals. Combine all ingredients except peaches. Blend well, and place batter in dutch oven on foil. Add drained peaches. Place lid on oven and cover with hot coals. Cook for about 30 to 45 minutes until cake pulls away from sides of the dutch oven. (Use single layer of coals under dutch oven and control heat carefully to prevent burning.) Adapted from "Woodall's Campsite Cookbook"