There are many topics covered in your high school health class: CPR, basic first aid, reproduction and drugs. Those are all perfectly suitable for teenagers to learn. Sadly, there are just as many health issues that should be covered, but aren't. Luckily, Cracked is there to help pick up the pieces. They have 10 lessons, but I want to comment on 2 of them.
Lesson #3 is about how to cook cheap food that won't make you fat. This is something that should be a mandatory part of college orientation. Cheap food is made palatable by making it high in fat and salt. This makes it easy to eat the food and not break the bank, but it will expand your waistline. That's why those cheap burritos are kinda tasty, but not satisfying at all. It will also ruin your palate for years. If you get accustomed to high-fat, high-salt foods, anything that doesn't meet that will not taste "right." It will only be through retraining yourself that you will get back to enjoying food that is quality.
Lesson #4 is that losing weight will involve some level of suffering. I think that suffering is a bit harsh, but the point is valid. You won't lose weight without some effort and struggle. There are no magic pills that will make the fat vanish. You will have to be more active than you are currently and you will have to eat fewer calories than you do now. I highly recommend that you find ways to take in fewer calories without reducing the volume of food tremendously. I also hope you can find ways to move that you find enjoyable. This will eliminate the suffering part of their lesson, and hopefully will make the effort seem as effortless as possible.