I was a diehard smoker. I started at 13. I managed to keep it to half a pack for at least 10 years. Then it increased significantly. God eventually told me that I had to quit or I would kill myself.
As I wrote in another thread, I did quit, but it was actually more difficult than natural childbirth. But fasting is a church tradition. Fasting doesn't always mean going without food. That's for those folks who have a high baseline. I once asked God why He didn't call me to fast, and the Spirit answered that he did, but he was calling me to fast from my excesses. I had to do that before I could ever hope to reach what was considered Christian fasting.
I would strongly urge to to switch to nicotine gum or vaping. Not to make a switch permanently, but as a step on the road to being free from it. God knows that I'm a baby and I like the bandaid pulled off slowly, so that's how He lead me. With gum or vaping, yes, you still get nicotine, but without the carbon monoxide and other bad chemicals you get with smoking cigarettes. There will be some withdrawal, but it can be bearable. Green tea is something I found effective to cope with it.
If you choose the gum route, you can start at 4mg and work down to 2, and then cut the gum in half until you are free. If you vape, you can buy lower and lower concentrations until you either stop or have a 0% nicotine vape juice.
I pray for God's help with you wanting to quit and quitting.