> Obesity rates suggest people eat far more than they need to.

Obesity rates are also higher among poorer segments of society than wealthy, so it isn't necessarily a given that obese people will choose to eat less just because doing so will make them poorer due to higher prices.

They could eat less, though, and would be healthier for it.

It's likely possible that the lack of self-control that is sometimes related to overeating correlates with lack of self-control in other areas such as saving money or avoiding debt.

But that's not popular to talk about; nobody likes hearing about personal responsibility anymore.

It can also be a learned reaction due to past experience. Shortage or hungry times resulting in an instinct to overeat when food is available to act as a buffer should bad times come again.

American kids are obese, too.

Regrettably, calories are not the only concern. Modelling the cost of a good diet is hard.

Potatoes, beans, rice, etc., are cheap and healthy.

Obesity reates in the US, from my observation, are a compound effect of the unavailability of affordable, healthy ingredients (fruits, vegetables) and cultural factors (a custom of never cooking healthy meals, for instance rice and vegetables, instead of consuming carb-heavy burgers and sugary milk shakes and coke at fast food outlets).

Friends in the US drove school buses during the day and worked at Wendy's at night, only to give back a substantial part of what they earned to Wendy's to cover their dinner there. They didn't even realize what slavery they were caught up in.

> unavailability of affordable, healthy ingredients

I hear that a lot, and it simply isn't true. A bag of apples is cheap, so is a bag of beans, a bag of rice, a bag of potatoes, etc.

Some of the cheapest foods in the supermarket are an ordinary can of beans. Milk is cheap, too.

The truth in the lie is that the availability of easy to eat and healthy quantities of food is lower than it could be, and Americans love convenience.

It is possible to lose weight eating only at McDonald's but it takes effort.

The fact that Americans drink about 40 gallons of soda a year on average HAS NOTHING TO DO WITH ANYTHING GO AWAY.

(I'd love to do the math if all caloric sodas in the USA had corn syrup removed and fake sugars added what the result would be)

Hmm. Napkin math assuming its 40 gallons of sugared soda at a reasonable 20g per 8oz serving is 640 servings, 12800g of sugar, 51200 calories, or 14.6 lbs of empty nutrients on average a year if it all got replaced by calorie-free sweetener.

How much is 40 gallons? 426 12 oz cans of soda, 35.5 dozen cans, or 256 20oz bottles of soda.

I wonder if the bad quality of the majority of tap water has an effect on soda consumption. How much less soda would we drink if every residence had on-site water filtration?

> the unavailability of affordable, healthy ingredients (fruits, vegetables)

That's a complete lie. It's way cheaper to purchase healthy ingredients and cook than to get fast food. It's completely cultural.

Yes, and we have a culture of overwork so even if people did want to cook at home they’re too exhausted or short on time to consistently cook healthy meals.

If humans behave rationally and eating healthy is cheaper and healthier why don’t more people do it?

Look at immigrant households. Poor, overworked, yet they cook.

It's a matter of culture.