Calcium is water soluble, but not fat soluble. It is the fifth most dissolved ion in seawater. On the other hand, fat is soluble into calcium in the body. The calcium will exâ¦tract the fat from food in the digestive system, and they combine to form a foamy substance which is not absorbed by the body, and so the fat will be flushed out.
Studies show that it is about 20 percent of the resting metabolic rate, which is about 1,300 calories a day, not of the total metabolic rate, which is about 2,200 calories a day, so the brain uses roughly 300 calories.
The brain makes up roughly 20% of the body's metabolism. In other words, 20% of the calories you burn up in a day are being used in your head. This energy is used to maintain the ion gradients necessary for action potentials (the firing of neurons) and for transporting/recycling neurotransmitters.