Muscle has a nice store of available glucose -- and I don't mean just in glycogen storage, which is the first port of call for muscle energy. When you run out of the glucose stored in muscle, and blood glucose and liver glucose are also low, the body knows it can get more glucose from muscle protein to maintain the brain and other important organs. And that's exactly what it does: the hormone cortisol breaks down muscle into amino acids, then another hormone, glucagon, strips amino acids and turns the carbon skeleton into glucose.
I have an office job and compensate by lack of movement by running and walking everyday. I am training for a half marathon and am running 12-16km 3-4 times a week and walk every other day. I try and stick to around 1200 calories each day and am just not losing weight (5ft 9 and about 135lb) I am trying to lose a little bit of with but it jus won’t budge! I tend to gain and lose muscle pretty easily. Any advice? I just want to feel a bit smaller particularly in the legs which feel bulky from all the running. I am scared that if I reduce exercise I will put on weight even at 1200 cal as I spend most of the day in front of computer! Thanks
***Now here is the rub with study 2. If you compare the caloric intake between the overfeeding study and the “40%” caloric reduction study we actually observe similar protein intakes between the two studies (see table below). Now we need to take into consideration the two populations. In the overfeeding study there were 11 females and 37 males total and the mean participant mass was~75 kg. In the calorie restriction study there were only males and the mean participant mass was ~100kg. This may make up the discrepancy and explain the similar calories in the different context.