If it's going to taste like a cake it will probably have some fat and sugar or equivalents, but there are things you can do to lower the calorie content and make it healthier. For example, it's possible to make a sponge with more eggs and less butter - or even double the eggs and use no butter as in this recipe. You can also, as a general principle, look for low fat spreads rather than butter, or other ingredients such as low fat creme fraiche or similar rather than using cream.

From a health point of view, brown sugar or honey are often better than refined white sugar although the calorie count may be similar. Some people use wholemeal flour, which can be good in some cakes.

The BBC Good Food magazine or website (as in the above link) is a good source of healthy recipes, and if you click here you can find general tips as well as specific cake recipes.