5 kg is a lot to lose in 1 month and probably not safe to do; however, you should calculate your calorie needs and start eating a balanced diet based on how much your body needs.
Can you please tell us how old you are, how much you currently weigh and how tall you are? We can help calculate your calorie needs.
I'm 17 and about 85 kg and 5.5ft......So I really need to lose some weight....
Drink plenty of water, its key to many diets. Stick to a 600-700 protein calorie daily. For example...
Breakfast: two full eggs 140 cal.
Add some spinach mushrooms whatever veggies you like, even through in like one slice or turkey lunch meat or ham
Lunch: tuna wraps, 90 cal total for two cans of tune in water not oil, mix tuna with light mayo and pepper and lay it on lettuce
Dinner: 6 oz chicken breast is about 210 calories no skin or fat in it. Cook it as you please get it up with cooking spray, that has nothing in it, add veggies. I use as seasoning anything salt free, like garlic powder or onion powder, mrs. Dash
Always drink a bottle of water before each meal, but do not chug it, and try to get in 6 bottles to 8 bottles a day, you can have as much coffee or tea as you would like, just use sugar free creamer. Have a snack around an 1 1/2 hours after each meal like cheese sticker light and fit Greek yogurt or cheese and lunch meat rolled up together.