Both are iffy propositions. The diet foods tend to rely heavily on presentation to get diners to consider the offerings to be actual food. The "foreign" recipes often use minuscule amounts of specialized ingredients to give a familiar dish a slightly different flavor from the expected "mid-century bland." Then writers throw in a bit of casual condescension to help justify the mistreatment of original recipes.
So what can we expect from 1978's Family Circle Creative Low-Calorie Cooking? Let's try some "Quick 'N' Easy Oriental Fare":
This seems to fit the bill: dabs of soy sauce, some ingredients that don't really fit the cuisine, and "Oriental" to mean anywhere in Asia. As if to reinforce my points, the chapter notes, "Orientals [sic] are skimpy meat-eaters by Western standards; fish, poultry and soybeans are more their meat. Lamb and veal were unheard of..." So by all means, let's make a veal recipe with a sweet-and-sour sauce that's mostly sugar-free apricot preserves thinned with water.
The other "foreign" chapter, "Zesty Italian Dishes," has a bit of an advantage since Italian-ish dishes were probably more familiar to home cooks and some ingredients (such as Italian cheeses) were more readily available than Asian foods. The disadvantage, of course, is that Italian-American food tended to be heavy in the meat, cheese, and noodle departments, none of which were considered calorie-conscious. What could the book do to Italian food?
The "lasagna" is basically scrambled eggs layered with cottage cheese and tomato sauce before baking. Probably not terrible, but certainly odd, and perhaps a concoction that could get the cook run out of town if it were served to real Italians.