The recipe is fairly simple, limit caloric intake, stay active, eat healthy. I would suggest going a bit further than cutting "junk food"... I would try to limit or drop anything that is loaded with sugar, highly processed flours, or milk because they caught a reaction which gives you cravings once you crash from the sugar high, and tends to accumulate fat because your body things you have extra calories coming in. Slow burn carbs like lentils and beans are much better than say bread.

As to exercise... doing some basic strength build (2-3 days / week) and just making sure you walk each day will do a great deal for you. As others have indicated, backpacking is good exercise

--Mark