Maintainable one means cutting out on a lot of the tasty food. Big breakfast and exercising in the morning. Since exercising in the morning gets your body metabolism up and running till the end of the day. Exercising in the evening or night doesn't help nearly as much, as your body metabolism goes back down when you sleep.

Drinking a lot of water, especially in the morning helps. Eating smaller meals more often instead of one or two big ones is also helpful. Skipping meals will hurt your diet more than overeating. Remember - no junk food, fried food, no colas, chocolate or ice-cream once a week only. And beer hurts more than the pure alcohol drinks like whisky or vodka.