While much of the interest in the relationship between weight change and smoking cessation has focused on weight gain, several studies have also reported weight loss or no change. To assess determinants of the direction of weight change, this study followed middle aged smokers from before to after their participation in various local smoking cessation programs. Measures included caloric consumption, available macro-and micronutrients in the diet, taste sensitivity and hedonics, smoking behavior, mood and exercise patterns. Smoking status was confirmed by determination of salivary cotinine levels. Subjects who successfully stopped smoking could be divided in those who gained weight and those who showed no change or lost. These subjects were compared to those who continued smoking and could be divided into the same weight categories. Subjects who gained weight after cessation did not consume more calories but ate somewhat less protein and significantly more carbohydrate than quitters whose weights did not change. Percentage of calories as sugar, in particular, was increased. Regardless of weight change, subjects who stopped smoking showed increased preference for sweet taste. Subjects who gained weight engaged in significantly less aerobic activity than those who did not.