Re: It's a lot easier to just not eat it to begin with.
"Unless you are a serious athlete, you aren't going to exercise enough to lose weight. "
That's not true. It's very hard because it needs commitment.
Consider this : most people gain weight slowly - say 5kg a year, that's ~40000 Cals, and that's just ~110 Cals/day Even a weight gain of ( a huge) 15 kg a year is still equivalent to just 350 calories a day and that's just 1 chocolate bar. Weight gain is pernicious, not sudden. When people do try to seriously do something about it they want instant results hence the fad diets etc. If they try by dieting, unless by serious starvation, to lose weight the weight loss will so slow as to be disheartening given the hunger hence the constant failures.
If you merely diet you have to reduce your intake to 'normal, and that takes time to establish as everyone is different, different outputs, basal rates, environments, biological variation and basic diets. Compounding this is the measurement problem. (Day-day variation in weight can be quite large, even ± 1kg is a range of 16000 Cals, almost entirely water retention/loss but tracking true weight change is made very difficult when you might only be losing 0.05kg/day.)
Once normal ( for you ) calorie intake is known you then have to decide how much to lose and also compensate as you say for the dropping of metabolic rate that accompanies semi-starvation. What that is for any individual ?. If it's say 200 Cals/day (which is a <10% drop in metabolic rate) then that has to be added to the amount you have to diet. If you want to lose 0.7 kg/week (say) that means reducing intake by 1000 Cals/day and that's when it becomes hard. Most people will feel very hungry, cold and depressed. Normal social life becomes hard and any backsliding a cause for guilt. Is it any wonder that most overweight people fail ?.
But remember that weight went on slowly, without most people noticing, it's best removed that way. It does require long-term thinking. But if you've managed to establish a weight neutral diet then even walking 2 miles extra a day will lose you ~9 kg in a year. There are caveats to this, as you lose weight your exercise is less costly in Calorie terms so the loss/mile will gradually slow, you need to be careful about your 'normal' consumption drifting as one choc. bar will negate 2 whole days exercise. The gain is you probably won't feel as hungry as if you'd seriously reduced your calorie intake, you'll get fitter, you'll feel better about yourself, you'll go quite some way to reducing your risk of type 2 diabetes, and if you do this exercise outdoors you'll probably boost your Vit D levels.
Me, I did a lot more than 2 miles a day, I was lucky my job allowed me enough time to do this , running before breakfast, walking instead of lunch, and stomping around the hill in the evenings I did backslide and doing as much exercise in winter where I live was very difficult. But I lost 35kg and never regained it. I still average ~500 Cals/day exercise but my Calories intake has risen to match it.
Footnote : I gained ~25 kg over ~ 5 years when my only exercise was working all hours refurbishing a house that we bought. Lots of isometric exercise but not as much aerobic. Lots of eating of convenience food/beer. I f you remember that equates to just ~100 excess CAls/day