Like the spavined, dreamy-eyed diet freaks celebrated in this week's magazine, the Gobbler spends a good part of each day obsessing over his calorie intake. Unlike those healthful wraiths, however, he's not concerned about limiting himself to 1,800 calories over the course of a day; he's concerned about limiting himself to 1,800 calories during dessert. (Or, for that matter, 4,000 calories over a modest luncheon at some new, not very distinguished Italian restaurant). Already chubby before becoming a professional eater, the Gobbler got on a scale a couple of years ago and found he'd ballooned to a sumo-size 286 pounds. Ever since that horrible day, he's been forced to exercise, utilize steely self-discipline, and call upon the help of several long-suffering nutritionists. Briefly, a few summers ago, he got down to a slim 225 pounds. Recently, the scale's needle has been drifting back up, so before the Gobbler once again becomes grossly and irredeemably fat, here are a few of his common-sense diet tips.