When you're talking about weight loss you need to think about an overall KJ defecit - not where the KJ are coming from. Does that make sense?
I think they are finding that is not quite so simple as that, the type of food eaten is important. When eggs are eaten daily they do help with weight loss when compared to eating the same amount of kj's, but no eggs for breakfast, I posted an article about this in another thread. I believe what we eat is important as it helps to control our kj intake. If by dropping 2 slices of bread a day and having eggs or another protein helps to control our hunger and therefore overeating, then what we eat does affect weight loss.