Because, survival. Muscle is expensive - your body wants only enough to survive. Fat is life - your body wants all the stores it can afford.

This, our DNA isn't set up to maximise muscle mass. Big cats however are a good example of animals that are designed to keep muscle mass on - damn things can eat once a week, sleep all the time and look like they work out everyday

Right, I understand the idea.

I just haven't seen any studies on the idea that an empty fat cell will never be destroyed.

I have seen quotes like "your whole body is reconstructed over a period of years", i.e. cells have a lifespan, so if your body is reconstructing cells why would it put resources into rebuilding empty fat storage containers. Or, the other option would be fat cells are immortal, which seems to be extreme as well.

Just looking for some actual studies on this ...

ah, ok - get what you mean. To be honest I can't point you in the direction of any studies so any explanation from me would be educated guess work.

Ok, a quick google pulls up this article in the NYTimes referencing a study - have read the first paragraph or so and article is on the right lines of what you are after.

http://www.nytimes.com/2008/05/05/health/research/05fat.html

Thanks for the link, it didn't really satisfy my curiosity though :)

Obviously there are a lot of biochemical triggers for fat storage, muscle growth etc. Leptin has a very large part to play along with insulin, etc.

If something controls the fat storage levels, it makes sense that they will grow back after being removed via liposuction, especially if the person doesn't fundamentally change what / how they are eating. Their insulin resistance, leptin levels, etc will control this regardless of the actual surgery implications.

I'd be interested in a longer term study where an obese person undergoes something like liposuction, then also changes their diet to something more in line with low carb to fix these insulin and leptin issues and see if those cells actually regrow.