This one is pretty simple. If you have obese family or friends, you’ll develop habits similar to them subconsciously. Eating more or more frequently, or similar foods, etc.
Is it a “contagion”? Well, fast food is yummy and being lazy is easier than being active and fit. So there’s a significant pull if you’re exposed to it a lot.
It's really hard to get reasonably priced single servings of anything in the US. In food service establishments there at least used to be a push towards value in driving up portion sizes; if nothing else, to differentiate a kids meal from an adults. For items sold in stores it makes more sense to carry one size, or very few sizes, and efficiency pushes towards packages that contain more.
As an example; a single frozen pizza that I enjoy the flavor of is only carried in one size. A size reasonable for two adults to split as a large meal, which could be split further to a 'nuclear family' with some sides. Instead I'll gorge on it as my only meal of the day because that's the most effective way for me to maximize the value of that 'best market fit' product (I really detest leftovers).
> It's really hard to get reasonably priced single servings of anything in the US
It's the amount you take in vs the amount you expend. Putting it on your plate doesnt mean you must eat it. I went from morbidly obese to showing abs during covid and while doing almost 0 activity just by watching how the weight of what i ate affected the weight on the scale.
McDonalds and Kroger can serve me flintstone's size portions and I'll still be fit because I know that for my daily expenditure I need a certain amount. If I know I'll be expending more, i'll consume more. Am I hungry? Absolutely! But you are free to make the choice to eat when idle, or do other more productive things. Hunger doesn't mean starving and it's hard to train your brain to understand 'no'.
