Well done for getting active ☺️
Best and most effective way is through diet... as a start log everything on MyFitnessPal (download free and use the free version). Do this without trying to cutback. It’ll give you an idea of how much you are consuming each day and when.
Next. Ignore the MFP calculation for how many calories you should consume - it’ll likely be too low. Have a read here: community.myfitnesspal.com/en/discussion/680246/tdee-amp-bmr-what-they-are-and-what-to-do-with-them for guidance on calories amounts.
Focus on food quality, essentially swapping as much junk as you can for nutrient rich food. It’s hard though!! So make swaps gradually, don’t completely overhaul your entire diet in a week. Aim to swap something each week or month to make it a permanent, sustainable and enjoyable swap. For example, if you have a sugary cereal for breakfast (I’m including stuff like Cheerios in that) swap for porridge made with whole jumbo oats and mix frozen fruit, dried fruit, seeds, nuts etc in. Maybe then ditch sugar drinks. Obviously these swaps might not be relevant but you get the idea!
Over several years I gradually swapped from diet foods and drinks, processed foods to a largely whole food, plant based diet. I noticed my energy levels went through the roof and tastes changed. I rely on herbs and spices for flavour.
I gradually lost 4 stone this way. It took years. But I’ve maintained this weight for nearly 13 years now. Over this time I also massively upped my exercise levels from bugger all to cycling 10-16 hours a week. I also took up racing. Initially I fitted my exercise into my routine so I was forced into doing it - I cycle commuted. It didn’t take long for it to become a habit. Now I’m totally addicted. I couldn’t imagine my life without cycling.
Always eat your exercise calories back! I used to try not to in the hope it’d speed my loss, but I’d always end up several hours later emptying the contents of the kitchen cupboards in my mouth. It shouldn’t be about deprivation and a test of willpower, but making sustainable changes.
Prior to all this I’d literally tried every diet under the sun and of course they never worked due to the level of restriction.
I discovered lots of foods which are packed full of goodness which I LOVE to eat. These make up my ‘treats.’ Find yours.
You are doing brilliantly as you’ve already made the first few difficult steps.