I am reading an interesting non-Ayurvedic book at the moment called "Nourishing Traditions" by Sally Fallon. Whilst I don't agree with everything she says, she's done some really interesting research into fat, one of may favourite topics.
D was once a professional sports person and as such was put on a very low fat high carbohydrate diet. As soon as he stopped playing sport and started eating more fat he lost weight. True story.
Fat, especially saturated fat, is vital to human health. Sally Fallon brings to our attention the fact that human breast milk is extremely high in saturated fat. In France the rate of heart disease is less then half that of the USA and their staple foods include butter, cream and eggs. Similarly in China, the rate of heart disease is significantly lower in regions where they drink full fat milk.
Ghee, coconut oil and whole milk are all good vegetarian sources of saturated fat. These will especially improve concentration and reduce anxiety and depression. If you are worried about the mucous forming qualities of such foods take them in moderate amounts with cardamom, ginger and bay leaves.