This is more of a rant than anything else, but advice would be appreciated.
I am away at a boarding school most of the time, so do not have control about what I eat. The meals served in our canteen are generally greasy and very carbohydrate based. It is just about impossible to maintain your weight. In the just over 1 year that I have been away I have put on at least 7kg (I am not 100% sure of my start weight) I would like to lose enough weight to get back to what I was and then be able to maintain that weight - I do not want to be skinny, but I am having to contemplate buying a whole new wardrobe and I don't have enough money. I am planning to try and lose some weight over Christmas (which will be hard enough in itself) but am really worried that I will just put it all back on once I go back in January.
If you want to manage your weight whilst you're at school there are a few things you can do. For food, portion-control will help. If you aim to fill your plate at every meal with 1/2 vegetables or salads, 1/4 complex carboyhydrate and 1/4 lean protein you will find it pretty satisfying but it will be lighter in terms of calories. In a canteen situation, you just have to be assertive. Ask the server to put extra vegetables on your plate first and then ask for smaller portions of the other elements (meat, potatoes, sauces etc.) second... works pretty well. If they still shovel it on in big amounts don't feel obliged to clean the plate.
Where you have choices and you're in control e.g. snacks, drinks etc., go for fewer chocolate digestives & Somerfield cookies and more apples or bananas, less squash and more water ... small changes like that can make a massive difference to your shape.
The other side to the equation is exercise and you can be 100% in control of that. The more active you are, the more energy you burn off. It doesn't matter if you're running round a track, cycling or tidying your room... if you're not 'sitting down' you're helping things along. So even if your food choices aren't as good as they could be, getting yourself moving will balance things up.
Yeah I'm in the same boat - when I do rough calculations of calorie content of our school meals they're usually about 700-800 cals a pop, at least! It's so hard not to eat the deserts when everybody else is eating them too! We have a salad bar which is usually a good choice but still the veg is often coated in oil.