Any human biology/ physiology experts? Burning Muscle vs fat

naturallykat

Hello

I know a bit about physiology through my equine science course (anat & physiology inc. exercise physiology & nutriton for horses) but obviously we humans are different from horses, so I am interested in the human physiology of weight loss, and have a backrgound which means I can understand and want quite technical explainations, but I just don't know the human (not horse!) specific things.

This is what I currently would like to learn more about; which sources of energy are used in which preferential order with humans? E.g. in horses, their physiology is such that they will not catabolise their own protein for ATP generation unless they are starving, and all glucose and fat stores have been depleted. So for the horse this issue of "we want to make sure we are burning fat not muscle" is null and void.

Now I hear so many people worrying about being a fat skinny person, and losing muscle over fat, and I've caught the worry! Is a human more likely to use protein as an energy source than a herbivore (I presume that's why)? And if so, what are the rules I need to follow to ensure that when I exercise I burn fat not muscle?

And how, from a physiology perspective, does low carbing fit in to all of this? Will the body preferentially use dietary protein for energy over reserves in muscles?

Many thanks for any easy-ish to understand technical explainations that come forward

jackiemonx

we only use protein as energy source in starvation mode. always carbs n fat that get used, or just carbs

jackiemonx

we only use protein as energy source in starvation mode. always carbs n fat that get used, or just carbs

sorry except for atp which we use for sprint or power

inspiration345

Technically I can't explain but our body likes to use as little energy as possible to maintain us. If we are starving the body will burn muscles instead of fat because muscles are more metabolically active and it requires calories to maintain them. I am waiting for other better explanations so that's why I have written here so I can keep track of this post.

jayb0ne

I'm just finishing up my lunch break at work at the moment. Bump this thread though and if you haven't had any good answers by the time I get home later on I'll break it all down for you.

Jay

erickirb

Technically I can't explain but our body likes to use as little energy as possible to maintain us. If we are starving the body will burn muscles instead of fat because muscles are more metabolically active and it requires calories to maintain them. I am waiting for other better explanations so that's why I have written here so I can keep track of this post.

his is ao god simple explanaation. It is easier for humans to survive with a low caloric intake with less muscle as muscle requires calories even at rest, so as a survival mode the less muscle you have the longer your fat stores will last.

statia152

Bump

naturallykat

So what is starvation mode in this instance? Sub 1200 calories? or just catabolism, at any less calories than maintainance requirements?

(More technical explainations still welcome, but those so far have been helpful too so thanks )

ycc1964

BUMP

HMonsterX

his is ao god simple explanaation. It is easier for humans to survive with a low caloric intake with less muscle as muscle requires calories even at rest, so as a survival mode the less muscle you have the longer your fat stores will last.

That makes sense, in a way. I'm not saying it's not how our body works, just our body seems a bit messed up on that!

Surely, if it eats our muscle, it makes us weaker, and therefore less likely to GET more food?

Wow, I'm feeling feisty today! I'm even arguing with millions of years of evolution now!

C'mon! I'll take you all on! XD

naturallykat

Wow, I'm feeling feisty today! I'm even arguing with millions of years of evolution now!

C'mon! I'll take you all on! XD

:laugh: I like your fiesty-ness - god help any punch bag that's near to you today

Yes I do get your point, and I don't know the answer. Perhaps muscles are only used up to a point then fat?

Horses, I'm telling you, are so much simpler! Diet, fat, muscle when there's nothing else.

neanderthin

Humans don't store protein (amino acids) therefore to maintain nitrogen balance the body converts our reserves of amino acids for function and repair. Get enough protein through diet and give the body a reason to keep your lean mass, little will be lost.

busywaterbending

naturallykat,

hi, your body needs fat and protein for cell, muscle, nerve function; repairs; metabolisim, etc. While carbs are used soley for energy, fats and proteins are additionally used for body structure. Since fats and proteins are so essential to life, eliminating them or restricting them from the diet is what would result in poor health and muscle loss.

find out more in the link I provide in my signature below. That physics student sums it all up nicely.

PB67

http://www.bodyrecomposition.com/nutrition/nutrient-intake-nutrient-storage-and-nutrient-oxidation.html