I've really grown frustrated with the idea of burning muscle when dieting. It is a position I'd believed and espoused for a long time, but I'm abandoing the convential wisdom as it doesn't really make sense and there are studies that are starting to support the idea that we do not metabolize our muscle tissue.
Even maintaining our fat stores takes energy and loosing fat does, indeed, slow our metabolic process. That doesn't even count the additional energy needed to move that extra weight around. In short, loosing weight does make in harder to loose weight and does slow our metabolic processes, but not because of muscle loss.
Now consider the idea that our ancestors didn't get 3 meals a day and may go a day or two without eating or eating very little. But when the opportunity did present itself to make a kill, they had to have the muscle power to do so. They were also probably actively engaged in finding that opportunity to make a kill, so they needed their muscle power to keep that effort going. It would make sense then that we don't metaboloze muscle tissue and that our bodies are capable of surviving on our fat stores for some time. I did read a study recently that supports this position.
Fast forward to the space age and in support of space station extended stays, NASA discovered that in the absence of muscle activity and work, the muscles will atrophy starting within 3 days of cessation of the work. They had patients lay in bed without moving for weeks at a time and biopsied their muscle tissue. They did the same to astronaunts before and after space trips and discovered the same effect. I would postulate that often as we diet and don't exercise, it is muscle atrophy that gets us rather than muscle metobolism. Combine that with the phenomenom that as we age we loose muscle, that may be attributable to lower excercise rates (which may be aided by reduced hormone - or hormones are reduced cause we don't exercise?? ). There are also evidence that certain exercises actually increase the production of homornes like testosterone and Growth hormones.
The reason we supposedly metabolize muscle is to be able to produce the amino acids necessary for mucsle growth and energy. But if the calories we do eat contain enough protien to provide the nescessary amino acids, then there is no reason to metabolize muscle tissue. This is probably why high protein diets like Atkins and South Beach work as they focus on high protein and low carb. This causes an overal calorie restriction whereby we need to glucose (provided by ketones) energy rather than the amino acids. We burn fat, but not muscle.
So in my mind, the position about calorie restriction causing muscle loss by definition is archaic and invalid. I realize I may get a lot of pushback on this position and some may even offer studies to dispute my position; however, those studies themselves may also be archaic. I use my own self study as evidence in that while loosing weight this year, introduction of weight training has shown gain in strength and not a reduction that would be noted were I metabolizing muscle while dieting. I guess time will judge my position, but in the meantime I will practice and advise based on this premise.
Edit: I was doing a little more research on my new lifestyle of Intermittent Fasting and some of the studies show that among the hormone changes that occur during this is an increase in HGH (growth hormone). The recommendation was to do strength training at the end of your fast to take advantage of these increased levels and the post fast - break-fast meal. This can actually encourage muscle growth.
“Your assumptions are your windows on the world. Scrub them off every once in a while, or the light won't come in.”
― Isaac Asimov
“Being ignorant is not so much a shame, as being unwilling to learn.”
― Benjamin Franklin
