I used to be fat as well, though not as fat as you (my heaviest point was 225.75336 lbs while being the same height as you) Here’s some advice.
- Always weigh yourself.
This is very important because it gives you perspective. As a fellow tall person (hell, my name is Andrew as well) you can surely confirm that the changes of your physique aren’t easily seen until some time has passed. It will take a bit of time to visually see your progress. If you stop seeing change you will just give up, as being on a calorie deficit feels horrible. Having 1 month of crash diet going only to revert to your old eating habits is a waste of time.
- Start counting calories.
The approach that helped me was just keping a budget of calories I can eat during a day. It doesnt matter what you eat as long as its low in calories. Hell, you can even enjoy a junk food once in a while as long as you stay within your calorie limits. But again, never eat or drink anything if you don’t know its calorie content. https://www.nhs.uk/live-well/healthy-weight/calorie-checker/ is a useful tool. Or when shopping for a snack, look how many calories it has.
As you will soon find out, crisps, soft drinks and bread are among the worst offenders so cut these out completely. Vegetables make excellent snacks, especially carrots. Veggies are healthy, filling and very low calorie foods.
In your situation, the “status quo” calorie budget is around 3100 kcal. A good calorie budget would be around 2400-2600, healthy deficit but not high enough to make you hate yourself as much.
You also need to keep weighing yourself - as your weight decreases, the calorie budget must also decrease. You should recalculate your budget roughly every 11lbs you lose.
Finally, consider putting quitting smoking on hold until your diet is firmly underway. Quitting smoking and losing weight at a huge calorie deficit at the same requires iron will, which I doubt many people have.
Good luck. And remember it’s okay to snack as it will keep you sane. Just use veggies for that purpose, not some garbage high calorie food