It was the smoking. Stopped in 2012 and ballooned from 95kg up to 135kg within a year. Took me way too long to get back to a healthy weight for my size. Your eating habits will change, you'll feel hungrier often, you'll develop replacement cravings for the dopamine hits. Try to be aware of your behaviors, try to achieve a few seconds of actually living in the moment once in a while and enjoy getting to know a more unadulterated (because of different brain activity from loss of constant nicotine stimulus) you. Find ways to work out without inducing complicated new habits/rituals. Waiting for coffee? Lean your body against something, do minor body weight exercises throughout the day like that. Doesn't feel like it matters but it does so tremendously. You'll quickly find more ways to do exercises like that, it'll feel like a game instead of a chore and it'll become a habit without adding complexity and guilt. All the best to you and your journey. ✊

Yeah.. Deffo don't swap it for a worse source of dopamine.