I thought about it, and offered much of the following, using as my linchpin the idea that if you tell people they are gonna have to give up much of they like about eating and couch-potato-ing, they simply won't do it.
No more cheeseburgers? Right. And the horse you rode in on, too, pal.
The old, eat-roots-and-twigs-and-hit-the-gym-every-day advice is a waste of breath. People who are on the road already don't need to hear it; people who aren't on that path won't listen to it.
So, entry-level advice on health and fitness:
The two old reliables are still the best: diet and exercise. Assuming you are healthy to start out with, and if there is any doubt, get a medical check-up, then the easy methods that gradually ramp up seem to produce the best long-term results. Crash diets seldom work, save temporarily.
I mean, yeah, you can take speed and not eat anything for weeks, and that'll work temporarily, too. Or get liposuction. Not a lot of health benefits versus the risks there.
Diet stuff: Cut back on empty carbs, i.e. sugar. Cut down on saturated fats. You don't have to give them up, but if you are going to eat cookies, don't eat six, eat one. Lower your butter-cheese-milk-cream-eggs intake, same deal. Fat tastes great, but has twice as many calories per gram as protein or carbohydrates. And you probably eat more of it than you realize.
If you are gaining weight, you are eating more than you burn. Don't try to fool yourself into thinking you are getting fat eating one lettuce leaf a week. It ain't so. 97% of us gain weight not because of any kind of hormone imbalance but because we eat too much, and usually too much junk food. If you are among the small percentage of people with really screwed-up metabolisms, you probably already know it. If you didn't get that diagnosis from your doctor, but just think you are? 97% chance that you aren't.
I don't count calories and I don't think that's the best way, but the physics are simple: If you eat more than you burn, you will gain weight. That's how it works, and unless you live in a realm wherein magic holds sway, you can't lay it off on anything else.
Let me repeat it: That's how it works. That is how it has always worked. Barring some kind of change in the way thermodynamics roll in our universe, that is how it will always work. You can't get around it. Don't waste your time trying.
It's not considered politically-correct, but if you don't like the shape you see looking into your mirror, it's because of what you did–or didn't do–to get it. Excepting congenital conditions. If you went from digging ditches to pushing paper, you need less fuel. If you hurt your leg and can't walk, you need less fuel. If you eat the same way you did when you were doing more, you'll gain weight.
If you like beer and you drink it, go ahead and have one once in a while; don't have three or four. Eat more filler, fruits, vegetables that offer nutrition but not many calories. If it took twenty years to put on the weight, you won't drop it and keep it off in a few weeks. The human body hates change.
Don't hit the scale every day; check once a month. The mirror is a better indicator than the scale anyhow, and dropping pants sizes is healthier than dropping pounds -- if you gain muscle, that weighs more than fat, so you could get smaller and tighter but not lose much weight. Forget the BMI scale, it is a ratio that has nothing to do with fitness.
Exercise is best if it is something you like to do. Failing that, something you can get used to doing. Walking thirty or forty minutes a day is a great start. Riding a stationary bike, dancing, basketball, swimming, whatever, the trick is to make it a regular habit. Weights in the gym will shape you and make you stronger, but that doesn't slim you down as fast as aerobic stuff. You burn about as many calories walking a mile as you do running one–same distance, but different amounts of time to get there. You can take it slow.
Ideally, a combination of weight-bearing exercise and aerobics, along with a diet that cuts down on junk food is the path I'd offer. Exercise alone isn't enough, you have to do an awful lot of it to burn up one chocolate bar. Diet alone won't make you fit.
But you have to do it–if you want to bad enough, you can.
Good luck.
To that, I'll add that the psychological factors of fighting extant flab are sometimes most difficult. Much easier to stay in shape than to get there from way out-of-shape. And fats and sugars are potent, they kick on the same receptors as heroin and nicotine, so just saying "No." won't be easy. You got to walk that lonesome valley by yourself, and if you don't do it, it won't get done.
Anybody who promises you that you can eat anything you want, as much as you want, and you don't have to exercise to lose weight and get in shape is either selling something or mad as the March Hare and the Hatter together. You can get it, but you will have to work for it.