Question about how to stop believing a thought

I had a great coaching call this morning and I wanted to follow up to get some more details on one point. I have two thoughts that I believe – “I should cook all of my meals” and “I don’t want to cook (I will get my meals at nearby salad bars)”. The coach asked why do I want to believe the first thought. And I said – I don’t want to believe it, I just do. I’ve always had that thought. And then she said – it’s a choice to keep believing it. And then I sort of lost the thread of the conversation a bit while I pondered is it really a choice. I guess the idea was – I can decide to not believe the thought “I should cook all my meals” any longer. But how does that work if part of me still believes there would be a benefit to me cooking (save money, control portions, control quality of ingredients) even though I don’t want to (don’t like it, takes too much time, etc)? Hope this makes sense. Thank you.