Can we predict calorie consumption so accurately? and could this partly explain yo yo dieting?

I've got two questions in my mind that I've wondered about for years.  Do we really burn calories as predictably as scientist say we do? and if not, could this explain why you you dieting actually encourages us to put on weight in the long term even though we may be eating less than before?

How could they be linked? Well yo you dieting often leadds to losing muscle mass. This is a key part of metabolism thus it's possible to eat the less than you did before and still put on weight. But is that the only explanation? if our bodies have the capacity to become more efficient and utilising energy then people could be assuming they're in calorie deficit when they aren't. There could alsobe other things to consider if calorie consumption is not as predictable as we're told. 

So why do I question what we're told as fact?

Mainly because I don't remember any one actually putting a full solid argument in front of me. I feel it's rather assumed and everyone is focusing they're attention on what they think is the real place where improvements will come. 

I could go into a real technical debate examining the krebs cycle and looking at actin myosin coupling to see where energy wastage could be adjusted.  I don't want to here, mainly because I covered these topics a long time ago at uni and need to re investigate for that kind of debate. I just have this lingering feeling that it's not quite complete. 

The wider reasons I feel it's possible is because it's recognised that humans are extremely wasteful of energy. You can tell this just by realising that wqith every muscle movement we generate heat. This means energy for movement is going into heat not just into movement. Thus we're wasteful. I forget the percentages but I believe it was in the region of 40% emitted as heat. That's highly wasteful. 

The same goes for digesting food. We expend energy to digest food. Some of it escapes as heat. Again that's wasteful. This is happening all the time. Yet evolution isn't generally that stupid. there are plenty of examples of animals that are wasteful during period of feast and efficient in periods of famine. This has been shown with vitamins and minerals in rats and other animals so why wouldn't it be true for energy. Take this further, this is the greatest feast man kind has ever known. There's more food available to us than ever. Particularly high fat stuff which we know has the most calories. So isn't it possible that our bodies just don't need to be efficient at the moment?

Is it possible that our muscles have ways of working which generate less heat and thus save energy. Is it possible that certain bodily functions are curtailed when there isn't so much fuel around. 

Just thought I'd pose the question. If there is sufficient reasearch to prove that energy consupmtion is predictable. That every inch of muscle always requires exactly the same energy for the same work then fine. That all mitochondria are exactly equal in energy intake and output. I'd like to see it though and see what debate there's been. 

I'd also like to know how to measure changes in calorie consumption as changes in technique occur as people learn, get injured, or change their muscle mass or improve fitness. This all has an impact in how efficient we are and thus how many calories we need. 

As for Yo Yo dieting. I'm really asking whether it's possible that our bodies could actually become a lot more efficient than we're told they are. If they can then the processes involved need to be understood by any one trying to lose weight because if you teach your body to be much more efficient then you're going to have to do a lot of exercise and eat next to nothing in order to lose weight.