I was having a conversation about it and the other party - a 40-something woman with a sedentary lifestyle, approx 160cm and overweight at 80kg - was trying to convince me that she needed 1800kcal/day to maintain.

She was gobsmacked when I told her I was at 1600kcal (182.5cm, 95kg, overweight) and that represented a modest deficit, and tried to tell me that I needed 2000 to maintain.

Everyone’s overestimating their maintenance requirement, and getting fat as a result.

Worked example: 70% of adults in the US are overweight and 30% are obese. Note: that’s not 30% of the 70%. Straight 1-in-3 merkins are chubsters, medically speaking.

tl;dr: we all eat too much.

...but not that much of a thing (outwith certain medical conditions).

Losing weight is tough, especially when you get over the initial novelty and early gains from a caloric deficit, and into the long haul of maintaining self-discipline. It becomes very tempting to rationalise away one’s failure to lose a kilo this week on “water weight”, but it’s much more likely you just ate (or, if you’re not a diet pop person, drank) more than you thought or wanted to think.

You’re right - breakfast cereal is ridiculous and those “serving suggestions” are misleading at best. Other prime offenders are pop (soda), coffee (many people load their coffee with milk and cream and syrup and a myriad other things, none of which have any business being in a cup of joe), and of course processed food - even if you set aside the “ultra processed” issue, a lot of processed food is extraordinarily calorie-dense.

It doesn’t help that The Internet stands ready and willing to tell you that your weight is not your fault, you can and indeed should eat whatever you like, whenever you like. Furthermore it’s fine to be fat, because fat people are just as healthy (until they hit fifty and their knees and hearts and whatever all say “fuck you, I’m ruined”).

It’s all horseshit, of course. Anyone can lose weight at a caloric deficit. It requires a lot of self-discipline in the face of a epicurean environment designed to thwart you at every turn, and depending on where you live (food deserts suck) it can be really hard. But ultimately it can be done, and the alternative is worse. I think of all the things I fear in later life, losing my sight and my mobility* are top of the tree, other than dementia.

No-one says “oh, I know you shouldn’t smoke, but giving up is hard, and intuitive smoking is fine anyway, and grandma smoked a hundred a day well into her nineties. And grandad took heroin every day for fifty years and it didn’t do him any harm!”, so I’m not sure why being addicted to food gets a free pass the way it does.