Quote from Mvic:
This does not work, ask a samoan.
I think you confused veges and fruit with pork and eggs.

There's some good advice in this thread (from Thunderdog and others). The rest, not so good. The guy defending white sugar, flour and pasta is funny. Go and educate yourself before spouting off such ignorant and potentially dangerous advice.
To the TS, cut out crap like white flour, white sugar, white pasta, junk food, sugar covered cereals, soda etc.
All of that stuff has next to NO nutritional value whatsoever. That means your body is living off food that it can't really do anything with, apart from giving you health complications.
Eat more brown bread, brown pasta, oatmeal, whole wheat cereals, fish, chicken, lean steak, cereal, nuts, fruit, veges etc.
Eat this stuff and eat a lot of it, like 6+ meals per day. It will speed up your metabolism and burn fat, not to mention make you feel 300% better.
Taking some omega-3 fish oil tablets is also a good idea.
Last, exercise. Walking is fine, but if you're young and have 2 legs, there's no reason why you can't mix things up and sprint every now and then. You only need short, sharp sprints, they will work wonders for your lung capacity. Do this on grass, it's softer on the joints. Pushups are also good, and if you're strong enough, chinups/pullups.
What you're left with is a body which is burning highly nutritional food and turning it into lean muscle, whilst exponentially increasing your life expectancy.
I could go on and on, but maybe that's enough to wet your appetite.