<human>: First of all, greetings to the whole community.

It's been a little over 3 weeks now since I started what appears to be one of my most significant efforts to lose weight. I need to lose quite a lot, and my first target is around 20kgs; enough to bring me to a two-digit number. I think I got past the first stage, which most of you should be familiar with.

I don't know how I did it, but the "first few hard days" are past me, and in those three weeks I've managed to lose about 4kgs. Self-discipline coupled with just a little bit of exercise (mainly yoga and some simple muscle exercises), a loose diet of meat, eggs and a decrease in carbs, and a lot of water have brought me to 20% of my goal, and I couldn't be happier.

All that said, the last few days have been a little harder. My tight schedule has brought me close to ordering junk food (the culprit for my situation) more than once, and with every drop I achieve, rationalisation becomes harder and harder to fight against.

I'm relatively certain that one of these nights, after a productive day and a couple small victories, I will convince myself that it's okay to order a pizza to eat along with my movie or something. And what follows is something I've went through a lot of times. It'll become easier and easier to convince myself to order that pizza for _this one time_, I'll start gaining weight, I'll be discouraged, and it'll all be over.

How do I shake off these thoughts when they do occur? I've heard that replacing a bad habit with a good one works with many people, but I'm not entirely sure how I could satisfy my craving without hurting my effort.

Condense the text into a few key points
<bot>: I've successfully gone through the hard first days and I'm on week 4. Any advice on stopping myself from ordering _"pizza"_ (or whatever) when rationalisation kicks in?