Do you really want to change op as your post is a bit ambiguous?
If you do it is simple really, clear your cupboards of all fizzy drinks, processed crap, chocolate and sweets.
Make a meal plan, look online and pick meals you feel you can tolerate, but that are healthy, as am example
Breakfast,
porridge and blueberries
Egg and avocado on brown toast
Dorset cereals.
Mid morning snack, apple or orange and handful of nuts.
Lunch,
Chicken/ham/tuna with salad
Or a wrap
egg and bacon with tomato.
scrambled eggs
Greek yoghurt with strawberries for dessert.
Mid afternoon snack, ryvita with something you like on.
Dinner,
Unprocessed meat, with 4 steamed or roasted vegetables, brown rice,
Grilled fish, or chicken with a jacket potato and salad.
Dark chocolate for dessert.
Just some simple ideas, the most important things are;
Commit by clearing out all junk,
meal plan and shop for 4 days worth of meals and snacks, repeat
Do not add any rubbish food,
keep trying new simple recipes until you find what you like,
Try all vegetable and food at least three times to improve your palete and give yourself chance to grow to like decent food.
Set your 4 day plan and don't break it, plan what you will do if out, ie where and what you will choose to order.
You will possibly struggle in the first week, but by the second you will look and feel so much better and in a month you should really see and feel hugely better.
Good food will not make you lose weight, you probably have poor gut balance as your diet is so poor.
Good luck