You can’t outrun your fork. These are different parts of the problem. Also: achieving a reasonable weight makes it much easier to get into an exercise program.
I don’t think the first part is true though, any distance runner or cyclist that has experienced the “bonk” knows that they didn’t eat enough.
But yup if you’re very obese, running won’t be good for your joints. Swimming would be better, but unless you have a pool or live on a lake it’s much less convenient.
The first part is true. It is ultimately a problem of thermodynamics.
The distance runner or cyclist is not obese in your example.
There is simply no way to exercise enough if obese to create the caloric deficit needed.
This is all really part of the problem. Telling obese people to exercise more and don't restrict calories too much just doesn't work. What works if obese is a massive calorie deficit over time because an obese person has a massive amount of calories stored by definition.
It is just a much different situation compared to a distance runner that is already very learn. That person does have to worry about not consuming enough calories exactly because they don't have the stored calories the obese person does.
