Is Lasagna fattening?

Lasagna does not have to be fattening if made with premium grade ground beef with little or no fat. The white sauce is made with butter and flour, however the butter can be replaced with a good quality vegetable oil such as rice bran oil. This will reduce the saturated fat content.

For the cheese topping, substitute with low fat shredded cheese.

depends on how much lasagna you'd eat.

It depends on the contents. If you prepare lasagne using low fat ingerdients then it isn't as fattaning as normal lasagne.