Hi Steven, and welcome
There are two places to start for "what to eat"- what works for you, and what's in your best interests nutritionally. The second is particularly important as you're still developing (you may still be growing, and brain/ bone development continues until about the age of 25). I'm also an advocate of knowing your calorie allowance and working within that- I recommend eating within a range of calories that represents a 500-1000 calorie deficit on what you need to maintain your weight (although it's important that that number doesn't fall below 1800 given your development).
For what you "should" eat, look to the nutritional guidelines in the UK. Have a look at the "eatwell plate" for an idea of what you should be eating:
Eatwell plate This is a great place to start.
The NHS recommends eating 5 serves of fruit and vegetables a day (you probably see "this counts as one of your five a day" on packages. A serve is 80g of fresh/ cooked fruit or vegetables (weigh from raw), a small glass of juice (can only count as one of your five a day due to lack of fibre and high sugar content), or 30g of dried fruit (only counts as one of your five a day). You should also try to have as much variety in that as possible (while 5 apples counts, it only gives you one set of nutrients- five different things is better for you). I think most people can eat much more than that- fruit and veg are a great way to be able to eat a lot more food (thus satisfying hunger) on a low calorie diet, plus they're very nutritious. Some countries (such as Australia, where Trusylver is and where I'm originally from) say you should eat more than 5 serves (Australia recommends 5 vegetables and 2 fruit- vegetables are probably more important than fruit, but both are excellent). Also remember that potato and sweet potato count as starches (like bread or rice), not vegetables, for the purposes of your five a day.
Another thing that might not be obvious is the latest recommendations by the NHS to limit red and processed meat to no more than 70g a day, due to increased risk of bowel cancer. 70g isn't a lot (most supermarkets advise a serving size is 125g). My personal response to this (yours may vary) is to increase the amount of white meat I eat (particularly chicken). I second Trusylver's recommendation that lean meat is an excellent option- personally I go for extra lean mince and carefully cut off (and throw away) all the fat on the meat that I eat.
Frying isn't necessarily bad- it can be, but it depends on how you do it. You need to limit the amount of oil you use because that can be a source of calories. I personally use Frylight (
Fry Light Sunflower Oil Spray (250ml) in Tesco | mySupermarket) for most of my frying, which is a calorie per spray (I typically use 6-10 sprays on my medium saucepan, so 6-10 calories; by way of comparison I need at least 6g of olive oil to coat my medium saucepan, which is about 50 calories). Stir fries can be an excellent way to cut down on the amount of meat you use (this one is very nice, although when I used it I used even less meat than the recipe called for:
Chicken & mango stir fry recipe - Recipes - BBC Good Food ) and incorporate vegetables into your meal rather than just have them on the side. At the end of the day, you need to account for the calories in everything you use to make something, not just the stuff you're consciously eating.
Watch out for the starches (grains, potatoes, pasta, rice, etc)- they're very good for you and you need to have them in your diet, but they can be reasonably high calorie. Bread is particularly bad, especially given it's not filling. Make sure you get the serving sizes right (e.g. a serve of rice is 50-75g, most people seriously overpour this) and try to supplement with something that's lower calorie.
Dairy is also important- you should aim to get 3 serves a day. Try switching from blue to green or green to red label if you can stomach it- you'll get used to the difference and you'll save yourself calories. Watch for cheese, it's incredibly high calorie most of the time (except for things like low fat cottage cheese).
Try to cut down on added sugar. Sugar is a real calorie kicker (about 20 calories per teaspoon), and adds up really quickly. If you have sugar in your tea or coffee, or on your cereal, wean yourself off.
As for things that work for you, part of that is what will work with your family, although it sounds like you're lucky that they're willing to accommodate you. Other things to keep in mind are your tastes (if you don't like broccoli, don't eat it- although if you don't like any vegetables... you do need some vegetables unfortunately, they're essential), your appetite (how hungry do you get, how much do you need to keep you full, do you need to snack, etc- the more you need to eat/ snack, the lower calorie density your food should be- e.g., you can eat way more courgettes- 17 calories for 100g- than roasted peanuts- 579 calories/ 100g), and your schedule (do you have to take your food out with you? how much time do you have to cook? etc). Try certain things- I'd recommend trying porridge for breakfast (a serve is 40g, but personally I have 45g because 40 isn't enough) because it's very filling (I have it with a serve of frozen berries and a little milk, made with water).
Have a look around the forum to see what other people are doing. In the diaries some people list their food (I keep quite a detailed diary and link to/ describe recipes most of the time). Have a look on recipe websites- BBC Good Food is a good one (it allows you to search within a calorie range)-
Recipes - 7000 tried and tested recipes... - BBC Good Food - and Taste Australia is another one of my favourites (use advanced search and look for "low kilojoule"- divide kilojoules by 4.2 to get calories. There may be some dialect differences there as well as things that aren't as readily available, but they have some really good recipes). I've also set up a thread for recipes with meat in them:
http://weight-loss.fitness.com/club/48894-omnivore-cooking-recipe-club.html and there's another one with vegetarian recipes:
http://weight-loss.fitness.com/club/48149-vegetable-dish-cooking-club.html
Don't expect miracles- safe recommended weight loss is about a kilogram a week (a little bit more given you're over 100kg, but probably no more than 1.5kg a week on average). Keep in mind that you're doing this for the long term, and don't get discouraged if you don't see exactly what you want immediately. Just keep plugging away- and if things don't change in a couple of weeks, then I'd recommend seeing if you've made any mistakes (miscalculated needs/ calories consumed, for example), and if you haven't, talk to your doctor and see if there are any other underlying issues causing difficulties (for example, I have an underactive thyroid which makes it difficult for me to lose weight if left untreated).
