Thanks so much for taking the time and effort to look the question up. Ok, my confusion was between answers D and E. When I took the preptest, I selected E. Here's why...
According to the nutritionist, for *MANY* (not all) people overconsumption of carbs can lead to overproduction of insulin, which in turn leads to extra fat being stored, i.e. makes you fat. Hence, can we not reasonably conclude that if you don't produce that extra amount of insulin, you won't store that extra fat that you would if you did produce that extra insulin? Thus, if you're not gaining any fat by eating tons of carbs (since you're not producing extra insulin), if you decide to cut back on carbs you won't lose any weight either since you're not gaining it in the first place.
The reason I didn't go with D is because I didn't feel that I had enough information to conclude that you should cut back on high carb foods instead of just cutting back on fatty foods. People who wish to avoid gaining body fat could also just cut back on fatty foods, no? Oh, and also, you could be one of those people who doesn't really gain weight by eating carbs, since the stimulus DID say "for many people, a high intake of simple carbs..."
I think there's something about answer choice E that I may be overlooking, and I have a few ideas but I'd like to see what you think before influencing your opinion.