Whatever you can it, cellulite in exercise-book terms refers to the dippled fat that accumulates on the hips, thighs, and buttocks of many women--mostly over thirty--even if they're slender. Nicole Ronsard first attacked it in 1975 (in Cellulite), and shaped herself a bestseller. What more is there to say? Larry Melamerson, currently of New York Kounovsky Physical Fitness Center, insists that his daily ten-minute routine--an improved program--can end the curse of flabby bottoms, saddlebag hips, and cottage-cheese thighs. He likens the cellulite-laden body to a u-pipe clogged with fat--illustrations make the image quite clear--and builds his program on three simple principles: awareness; substitution; and moderation. Exercise books, especially by salon stars, tend to be padded and gushy, but this is brief, low-keyed, and thoroughly practicable. The dietary recommendations are standard (count calories; restrict fat, sugar, and salt), the exercises themselves are geared to problem areas only, and the significance of the problem is not inflated (""an unesthetic condition,"" ""not a disease or a health problem""). All in all, one to watch.