How enthusiastically should the use of monounsaturated fats be encouraged?

The Garg study diet supplied 50% of the calories from fat (33% from monounsaturated fat), which eliminates much of the bulk from the diet. Substituting monounsaturates for carbohydrates in the diet translates into giving up 120 calories from a carbohydrate source (very large potato, 1 1/2 slices of bread, 1 cup of cereal, etc) for a tablespoon of olive oil. Somehow that doesn't seem like a good exchange. Abbott et al substituted complex carbohydrates for saturated fat in the diet and accomplished the same result as Coulston et al with a low-carbohydrate (40%), moderate-fat (40%) diet. The American Diabetes Association suggested that if diabetes was poorly controlled and hypertriglyceridemia a problem, monounsaturates might be useful to maintain caloric balance. However, in light of the high incidence of obesity in persons with NIDDM and recent studies on the ease of dietary fat storage in adipose tissue, should fat of any kind, including monounsaturated fats, be substituted for carbohydrates in the diet of persons with diabetes?