It’s also incredibly important to remember that not eating anything at all will trigger your body to turn your proteins and muscles into fat in attempt to help you survive longer. Do not just not eat for a day or few. I have a friend who tried that. Didn’t work.
That is not all that accurate; “muscle mass” lost during a relatively short fast (1-2 days) is due to glycogen depletion - ie. you’re burning your sugar stores, and your body sheds 3-4mL of stored water for every gram of glycogen burned.
If you stop to think about it, it’s a bit nonsensical to claim that the body would burn additional calories (that it doesn’t have) to convert existing muscle into fat, rather than just burn existing fat stores as a fall-back source of energy.
Muscle breakdown only really begins when the body starts to experience a significant shortfall in required essential amino acids over a prolonged period of time, or significant physical stress.
“In order to produce glucose for energy, the body starts to use proteins stored in the body. Now, proteins are most commonly associated with one’s muscle mass, so you’re right to think that gobbling up your own protein will have a negative impact on your muscle mass. Proteins release amino acids, which can be converted into glucose; this is good news for brain, but extremely bad news for your body and physical appearance.
You’re right to say that fasting for shorter periods can and will burn fat, but after some time you will begin to burn your muscle mass because fats do not have the stuff needed to operate your brain. Fasting for a day is not enough to do that, but multiple days can and will do this, and I personally know a few people who neglect food for multiple days.
It’s also incredibly important to remember that not eating anything at all will trigger your body to turn your proteins and muscles into fat in attempt to help you survive longer. Do not just not eat for a day or few. I have a friend who tried that. Didn’t work.
That is not all that accurate; “muscle mass” lost during a relatively short fast (1-2 days) is due to glycogen depletion - ie. you’re burning your sugar stores, and your body sheds 3-4mL of stored water for every gram of glycogen burned.
If you stop to think about it, it’s a bit nonsensical to claim that the body would burn additional calories (that it doesn’t have) to convert existing muscle into fat, rather than just burn existing fat stores as a fall-back source of energy.
Muscle breakdown only really begins when the body starts to experience a significant shortfall in required essential amino acids over a prolonged period of time, or significant physical stress.
“In order to produce glucose for energy, the body starts to use proteins stored in the body. Now, proteins are most commonly associated with one’s muscle mass, so you’re right to think that gobbling up your own protein will have a negative impact on your muscle mass. Proteins release amino acids, which can be converted into glucose; this is good news for brain, but extremely bad news for your body and physical appearance.
Such a rapid depletion of the body’s proteins will result in a weakening of the entire body, diminishing muscle mass, and decreased libido. In women, this can result in a total shutdown of the menstrual cycle.” [https://www.scienceabc.com/humans/what-would-happen-if-you-stopped-eating-altogether]
You’re right to say that fasting for shorter periods can and will burn fat, but after some time you will begin to burn your muscle mass because fats do not have the stuff needed to operate your brain. Fasting for a day is not enough to do that, but multiple days can and will do this, and I personally know a few people who neglect food for multiple days.
And hormone issues can play a huge role in how your body processes and uses the fuel you give it. It’s not always as simple as calories in/out.