[stavros]

> You'd likely never produce enough energy to offset the energy used to create the inverter.

Even if you did, the energy going into the bike isn't usually green. It's very, very far removed from the sun, especially if you eat lots of beef. Even if you don't, lots of gas was spent to get your food to your mouth, so you'd be much better off just not wasting the calories.

[SamBam]

This argument is only relevant if you weren't planning on exercising anyway.

If you were planning on exercising, any energy you feed back is completely "free," regardless of your food source (minus the embodied energy of the equipment you hook up, as above).

[stavros]

Yes, but if you were planning on exercising just to burn calories, just don't eat them in the first place.

[NathanielK]

Why? Exerting yourself and pumping out the watts forces your body to adapt to that and become stronger. Certainly better than being "efficient" and letting your body adapt to being sedentary.

[stavros]

Imagine eating French fries all day and then exercising to burn the calories. It would be better to not eat them in the first place.

[BizarroLand]

Imagine thinking that human bodies are CICO machines with no other function or utility

[stavros]

Imagine not being able to comprehend the sentence "if you were planning on exercising just to burn calories, just don't eat them in the first place."

[teaearlgraycold]

More in and more out is better than less in and less out.

[stavros]

Certainly not from an environmental standpoint, but why from an exercise standpoint?

[teaearlgraycold]

Depending on what you eat you could still be well below the average environmental impact of a resident of an industrial nation. If you're vegan/vegetarian then 4000 calories a day from beans would be far less impactful than a 2000 calorie diet of meat.

Fit people need to eat more. Muscle takes calories to maintain. You can't maintain muscles without exercise. Your body expects that you're running down prey on a periodic basis. If you don't meet those expectations not everything will work as it should.

[nradov]

Humans evolved to move around a lot. Avoiding exercise to save food will lead to a host of ailments. Sarcopenia is a hidden epidemic among older people in developed countries.

[stavros]

But we aren't talking about avoiding exercise, we're specifically talking about exercise as a way to burn calories.

[micromacrofoot]

Withering away and dying to stop global warming