Fitness is easy if you are a healthy young man. Its often automatic, requiring no input. 1 pound of muscle burns 50 calories per day at rest. If you have more muscle, you are burning more calories just by having it. As you get older, your body starts going through changes. Muscle diminishes, parts of you change shape, and hair appears in places you never had it before. Its pretty easy for a 17 year old to talk down at fatties. When they wake up at 35 and find their weight has doubled, many of them wonder what the hell happened.
I started getting fatter in graduate school (fat is a relative term, no one would ever describe me as a chunk, but when I started in WoW early in grad school I gained 15 lbs over the next year).
There are a lot of different kinds of exercise. If you are obese, you have a different problem than I had, and one that requires a different approach.
I'm a little older now, and I've been excercising regularly for a little more than a year. I've seen huge results only in the last three months. The reasons for lack of results:
-I was doing it wrong.
There are two main mistakes people make in fitness. The first mistake is "cardio only" and conversely "resistance only." You see, fat cells are fat cells. Muscle cells are muscle cells. You never get fewer fat cells, you never get more muscle cells. You alter the ones you already have. You need to intersperse cardio with resistance training to improve fitness in any meaningful, lasting way. Also, cardio is boring, so go to "spin" classes. It helps a lot.
The gym I go to has personal trainers. ONe day I was lugging huge weights on a machine, and he came up to me and basically said "OH MY GOD STOP THAT IS SO WRONG" in the nicest way possible. He showed me the right way to do it. The difference I could feel. It was amazing. So I signed up. Costs 150 bucks a month, 1 session per week. So worth it. This single investment has made more of a difference for my personal fitness than anything else I've ever done.
The most important thing was to have someone there teaching me how to do various exercises correctly. Fitness takes time and work, and you want every bit of effort to "count" for something. Walk into any gym and you'll see tons of guys yanking huge amounts of weight, with fast, explosive movements. This is what I imitated when I started in the gym. It is so, totally wrong, and if you do it, you won't get any meaningful results either. Because its easy. If its easy, you're doing it wrong.
If you are in a university, there are gym facilities to use. Use them. Its easier now than it ever will be again, and you'll lose 10% muscle mass every decade after your 30s.