I love Gary Taubes, don't get me wrong. He is almost the single reason that I have turned my weight around.

That said.

I do believe a calorie deficit - even on a high-carb diet - can cause weight-loss, especially if you are exercising.

It is true that calories in calories out is a weak formula at best for many reasons. In the end though if you are consuming less calories than you are burning it is thermodynamically impossible for you to retain weight.

The main problem arises from the fact that after exercising you do work up an appetite. For those of us on this forum I would say it is generally difficult enough to ignore food cravings even under normal circumstances - let alone when you burn an extra 2k calories on a treadmill and your body is screaming at you that it wants it's fuel reserves back. If that isn't bad enough your body may even lower it's metabolism to keep up with the calorie deficit, even if you are exercising.

I think this is where LC diets, particularly ketosis trump other diets. Once you are happily running off of body-fat you have all the energy you could possibly need... Your body is happily burning its fuel reserves already - as it was designed to do in ketosis.

So I guess what I am trying to say is that I am theorizing that exercise while on a low-carb diet doesn't come with the problems it would on a higher-carb diet - "working up a hunger". Your body recognizes it has no need for extra fuel, even after exercising as it has hundreds of thousands of calories (millions?) readily available to it.

I have absolutely no research, studies or personal evidence to back that up... It is just a personal opinion.