Wogsterca wrote:
"Now suppose you buy the same meal, you eat it, get on a bicycle and do a ride up cardiac ridge, burning 2000 calories in the process. Same input, but now you burned 4000 calories, so your down 1000 calories, the body will use it's fat stores to make up that deficit. You lose weight. This is why diet and exercise are combined to provide weight loss. "
If that worked, it would be great. You've simply ignored my premise, though, and stated your own.
Let's look at the numbers you've listed another way:
- Your body needs: 2000 calories
- You burned with a bike ride: 2000 C
- You need to put back: 4000 C
So:
- You eat: 3000 C
- You are negative: 1000 C
In my scenario,
you will put those missing calories back into your body because, as I wrote above, you will be hungry enough after your ride to consume at least 1000 C. Maybe not that night, maybe not the next day. But your body, on the most basic physiological level, will demand that balance be restored, and it won't be satisfied pulling energy out of fat tissue; your body will want you to put energy back in through it's gaping mouth.
Human beings simply will not tolerate being hungry.
In the abstract, yes, I agree with you, Wogsterca, it's calories in and calories out. In reality, though, and especially in societies where unhealthy - i.e. fattening - foods are too readily available, it's too often extra calories in and not enough out.
Once we have gained extra weight from eating too many Big Macs and shakes and breads and potatoes and candy bars, getting rid of that extra weight is extremely difficult, at least for most people. At that point, no matter how much we exercise, we will simply want to put back as much energy as we expend.
Think of the phrase, "I worked up a good appetite." That's what happens after a long bike ride, or after chopping a few cords of wood, or climbing a mountain, or exercising at the gym. We don't finish those activities, if we're overweight, feeling as if we don't need to eat. It's just the opposite, no matter what we weigh.
And cutting down on the amount of food we eat - once we are fat - won't work, either, because over the long haul, we will not let ourselves stay hungry. We will eventually eat to assuage our hunger. Maybe not that day, maybe not the next day. But we know that eventually just about everyone will put back on weight they've lost via exercise and by cutting down on their calories.
There is a way to lose weight, though, without starving ourselves (and without the need to exercise, although, as I wrote above, exercise is good for us). That way is to stop eating, as much as possible, sweets and starches. That is virtually impossible to do, given that these fattening foods are ubiquitous.