Wish there was a pill to solve this for us (phisically-)lazy ones...
You can start weight lifting, following a “Russian strength” program (just three exercises, heavier weight, small sets of 3-5 reps), and the experience noticeable changes within 4 weeks. And I’m not talking about a lot of time at the gym... perhaps 2-3 hours total of exercise per week.
Not only will you get strong, you will start burning more calories when you’re not even moving. Plus, you’ll feel more energy and more drive/discipline to eat better and go back to the gym. In fact, a common problem is wanting to go to the gym too often. (The older you get, the more recovery time needed between workouts... more workouts can actually be detrimental.).
And if you only have time to go to the gym once a week you can make visible progress in that much time. Three sets of five reps of squat, bench and deadlift is doable in 50 minutes and if you do it consistently once a week you’ll see steady progress for most of a year.
the biggest difference is, most likely, the amount of time you'll be able to spend in the gym and it might take you a little longer to get started properly as you'll probably have limiting deficiencies in mobility at first. but this is still negligible; one or two months really don't matter much if you plan to lift for the rest of your life. only being able to lift twice a week will still do wonders for your health, looks and wellbeing.
i can get in shape quickly now, but at first it took me 12+ months to get the technique down and it would have taken me 12+ months if i had started at 18 (which is not entirely accurate - there is not specific point where you'll finally "got it").
Luckily only the first few weeks are boring and excruciating, then your body starts responding and it actually starts to feel good.
...nope, I'm one of those humans miss-programmed to secrete dopamine and endorphines when slumping in a chair coding and eating chips, and to feel depressed to death when doing physical effort. For those other 99% of humans programmed with the normal response to physical effort that you describe: you don't know how lucky you are! (Anyhow, will carry on, ugly body + diabetes + heart-attack and/or stroke at 50 still sounds a bit worse than working out a bit feels :P ...still on the look for some pharmaceutical "cheat codes" though, there's gotta be some 0-days in the human body/mind that we can hack to get to avoid that work, though maybe risk/benefit might not be worth it here)
Yes, I do intend to challenge your position, but I mean no offense. Maybe the problem is not slumping nor coding, but the chips. The first step to fixing health, be it physical or mental, is fixing one's diet.