It sounds so simple but obviously if it was that easy no one would be overweight without a medical reason.
Not true at all - the foods that are around and that we tend to eat these days are incredibly calorific. Just getting a good idea of what your daily calorie requirement is and how many calories are in everything you put in your mouth over a few weeks will help you adjust.
If you're finding it impossible to keep within your daily calories, you're choosing too many energy-dense foods. A lot of them are hidden, too - fried foods are obviously covered in oil which is very heavy on the cals, creamy sauces are full of them too. You need to find favourite everyday dishes that are less calorific than your current ones, perhaps. You will not miss the calorific things you used to eat - they will be occasional treats and you will understand that they are far too calorie-dense to eat regularly. You just need a bit of time away from them, and to shed a few pounds to appreciate the difference, to discover that.
I've put on something like 12 kilos over the last couple of years due to much reduced exercise and just not thinking about calorie content too much - or portion size. The last couple of years just so happens to also be the time I've been living with my partner.
I cook, I try to make sure there's enough food so he doesn't complain that he's hungry despite eating his entire portion (I need to really crack down on that, he's overweight too and seems to have no interest in understanding that he doesn't need more food, he's just used to eating loads), this results in me cooking almost double what we perhaps should be eating sometimes, and he goes back for more without fail, despite it sometimes being my intention to freeze the extra portions. It encourages me to eat more too. This has now stopped, because I refuse to engage in competitive overeating!
Basic tips that don't relate directly to calorie counting:
Drink water or clear teas at every possible opportunity rather than juice/pop/coffee or tea with milk and sugar. You don't need the extra calories that just go down without you noticing. Appreciate the non-water drinks you have rather than going to them by default.
Up your vegetables and leafy veg, and reduce potatoes/rice/bread/pasta a notch. The former will help fill you up more than the latter with fewer calories.
Just be aware that if you eat starchy or sugary foods, you will likely feel hungry much more quickly than you would have had you eaten something else. You don't need more food. This is why you need to spend some time understanding how many calories you're taking in - or rather, just understanding what it is you're taking in overall, and how each thing affects your hunger. Once you understand that being hungry doesn't necessarily connect that well to whether you actually need more food, it gets easier to start choosing things that won't leave you feeling hungry more often.
I'm not one of the people you name but I felt the need to splurge this essay-length post in response to your comment, sorry. 