In general, eating foods that are full of antioxidants and phytochemicals will promote better health (which in turn can help you body to lose weight). Of course, the best sources of antioxidants and phytochemicals are vegetables, fruits, and seasonings (oregano, thyme, rosemary, and other such seasonings are actually plants in themselves and have their own antioxidants). In a dorm situation, getting in your fruits and vegetables shouldn’t be too difficult, but it could get a bit boring.
Most importantly, vary the foods you eat. Instead of having a plate full of lettuce, have a plate full of spinach, carrots, squash, beets, etc. Diversifying your diet will make the biggest improvement! Similarly, things like nuts, seeds, soy (tofu), cheese, eggs, and such are also commonly overlooked, but are often available at salad bars.
Aim to get enough protein, not just from beef and pork (which often has more calories), but through chicken and fish. Fish is especially good since it has omega nutrients. Pare this with some brown rice or whole grain pasta and some fruits/veggies, and you’ve got yourself a pretty healthy meal. Pastas in themselves also aren’t bad for you, but most dorm selections of these should be limited (often due to the sauce/oil that goes with them).
Although dorm food usually isn’t as customizable as other places, you can still look for items that are grilled, broiled, or baked as opposed to fried. Also, you can usually ask for less sauce/oil when they are putting your plate together.
So, diversify your protein, vegetables, and fruits. Avoid sugary, oily sauces and food items. Remember, soda, candy, chips, and other such junk foods are the only thing that can be COMPLETELY REMOVED from one’s diet. Meat (or nuts, seeds, beans, soy, etc.), fruits, vegetables, complex carbohydrates (especially brown/wheat), and even some fats (fish, nuts, olives) are good for you!
In general, avoid burger places. If there is a Chinese/Italian/Mexican/some-form-of-mea… place you can find healthier options. It may take practice, but you can learn to pick out the healthier stuff (generally, if the item falls specifically into the category of meat, carb, vegetable, etc. it will be much healthier than if it is a mass of greasy or sugary goo). Most places will have at least a couple healthy things to eat. If by some cruel fate they don’t, talk to your student council about getting some!