Yeah, because eating less is easy. If only overweight people knew that it would have a small impact on global warming, I'm sure they'd suddenly be able to cut back, even though personal health, physical attractiveness, and day to day comfort haven't been enough to get them to eat less. But yeah, a small potential impact on global warming will probably do it.
There's lots of "modest proposals" out there that would be just as effective as yours. Want to cut 5% of human energy consumption? Round up 1% of Americans and just shoot them. Mission accomplished! And why stop at only 5%? If we identified the 10% most intelligent existing humans and euthanize the rest, all our problems (aside from moral and ethical topics) are solved.
Wow! So telling people not to overeat--to save resources--is the same as rounding up people and shooting them! You YCombinator people sure are nuts!
Yet you'll gladly tell people to drive less, or to change their lightbulbs to LEDs, things that could either greatly inconvenience people or cost money. Eating less is free!
[reading before posting, apologies for a rambling reply]
Personally, I see it as a very similar question as "why don't people just stop taking drug X" (to avoid side arguments, substitute X for a drug you see significantly altering people's lives for what you see as negatively).
Weight loss is typically very simple, but that gets confused with easy. really quite minor behavioural differences can result in fairly extreme weight changes over time.
Perhaps it's simply that people are prioritising short term things over long term. Short term the beer I'm drinking is nice, relaxing and great. Long term it's negative since it's at least taking me over my calorie limit for the day.
The risks are vague and hard to intrinsically grasp, the benefits are simple and local.
I think there are also significant effects of what people expect. With so many people overweight, what people expect has changed. I don't have statistics, but I've heard a large number of people complain about their families declaring them "anorexic" while still being quite overweight or even obese. If you're surrounded by people telling you to have more, having an expectation that people should be larger, and many external sources telling you that losing weight is complex (requiring weird and extreme approaches)
Fundamentally, we've not really evolved to deal with an environment of near infinite food available through very little activity (not suggesting work isn't hard for many, but we can sit down all day and easily get several times our required calorie intake). We have evolved in environments where we needed to get as much as we could from our surroundings, and it was hard to come by.
Food is also one of the most common ways of dealing with stress, depression, or all sorts of mental disorders, minor and major. It's readily available and socially acceptable, and most people associate good feelings with many foods that are particularly high in calories. For some people, it's one of the only consistently rewarding things in their day.
How much is too much? Not everybody prioritizes health, enjoyment, etc. in the same way. It's easy to fall into the trap of assuming that our personal values are shared by all.
If you were simply expressing your opinion, that's perfectly fine. I only wrote this because it appeared to me as through you were attempting to portray what you said as an objective fact -- which it is not.
An easy measure would be: if all people on the planet would consume resources just like the people in a particular country, the number of planets needed to feed and entertain them should still be less than one. By that measure, I think Europe is somewhere between 2 and 3 and the US is beyond 4.
That measure doesn't deal with over population, which is a huge thing, and more likely to run out of control than consumption per person in a country. Although individual consumption is important as well.
For instance New Delhi is far more polluted than any US city, although energy consumption per capita may be 16 times more in the US than India.
In my opinion a measure like energy or resource use per square kilometer of land is a much better measure. Although it has its problems as well, such as land quality varying greatly between different areas, which would change the number of people an area of land could support in a sustainable way.
Sources:
Population and energy usage per country http://www.worldpopulationbalance.org/population_energy . This uses Population Reference Bureau; 2012 World Population Data Sheet for population information and uses U.S. Energy Information Administration 2012 for energy use information. This is on the bottom of the page linked.
For the Pollution index, it is Pollution Index 2016 Mid Year http://www.numbeo.com/pollution/rankings.jsp .
