Astrid, I see what you mean re the "low-fat" thing. I agree, most low fat packaged products contain way too much salt and sugar and are far worse for you in the long run.
I think my biggest beef with low carb diets is the effect it has on exercise. Glucose (a form of Carbs) is a major fuel source for the body and when too little carbs are consumed the body uses fat and protein to make energy. The problem is your body takes a lot longer to provide fuel from fat rather than glucose or glycogen so can really only be used when exercising at a low intensity. I think that the population as a whole should be undertaking more exercise and as such should be fueling their bodies appropriately but this is my personal opinion so please don't attack it!