Thought Experiment

[GringoMcGordo]

First of all this is in no way a real diet anyone should consider. The purpose of my posting it is I am trying to understand how much protein is burned for energy in calorie deficit vs what is used from fat reserves.

For the purposes of this, assume someone has a moderately high activity level, and their maintenance calories are 3000. The only thing they eat is 2500 calories worth of fat free turkey breast per day. 100% of the calories they consume are protein.

How much of that protein will get metabolized for energy?
What about at 2000 calories?
At 1500?

What I'm trying to establish in my head is at what point does not eating enough overcome the fact that you're still technically getting all the protein you need to do bodily maintenance activies.

Bonus reps if you can provide an equation and relevant variables.

[AdamWW]

Well, I don't know of any 100% fat FREE turkey breast, but I understand your hypothetical: a literally 100% protein diet.

There is no way to estimate this in such an extreme example, especially because the rate of gluconeogensis from glucogenic amino acids would likely up-regulate significantly in such an environment.

Short answer: no idea.


PS - Offering 'reps' when you have no rep power isn't really an incentive ;o)

[desslok]

Short answer is it will be different for literally everyone and dependent on multiple factors.

[SuffolkPunch]

Protein can be converted to carbohydrate - which in turn can be converted to fat. The body doesn't usually do the latter but will do if pushed.

Apart from the cost of using alternative pathways, I don't really see this as different to any other mixed diet with the same calories and adequate protein. If you are thinking about how recomping happens, adequate protein and a non excessive deficit are the only requirements. More than a certain amount of protein is not likely to increase the effect further. The body will prioritise energy production vs. growth of new muscle tissue

You aren't going to see an equation because there isn't enough data and you are most likely dealing with non linear and thresholding effects. I speculate that the chaotic combination of which would be pretty impossible to model mathematically.

[necon76]

How much of that protein will get metabolized for energy?
What about at 2000 calories?
At 1500?

350

[kingofturtles]

came in to say glucogenesis

[GringoMcGordo]

Well, I don't know of any 100% fat FREE turkey breast, but I understand your hypothetical: a literally 100% protein diet.

A lot of turkey breast is advertised as "fat free", but yes there is a small amount of fat in it. A bit pedantic but thanks for pointing it out.

There is no way to estimate this in such an extreme example, especially because the rate of gluconeogensis from glucogenic amino acids would likely up-regulate significantly in such an environment.

Thank you. These are the kind of answers I'm looking for. Not sure what that is yet but it gives me something to research.

PS - Offering 'reps' when you have no rep power isn't really an incentive ;o)

K. I have no idea how the rep system works yet, as you can see I'm new to the board. I assumed it was like upvotes on Reddit.

[GringoMcGordo]

Protein can be converted to carbohydrate - which in turn can be converted to fat. The body doesn't usually do the latter but will do if pushed.

Apart from the cost of using alternative pathways, I don't really see this as different to any other mixed diet with the same calories and adequate protein. If you are thinking about how recomping happens, adequate protein and a non excessive deficit are the only requirements. More than a certain amount of protein is not likely to increase the effect further. The body will prioritise energy production vs. growth of new muscle tissue

You aren't going to see an equation because there isn't enough data and you are most likely dealing with non linear and thresholding effects. I speculate that the chaotic combination of which would be pretty impossible to model mathematically.

Thank you! This is along the lines of what I was thinking, but you put it more eloquently that I ever could. My knowledge of biochemistry is almost non-existent beyond the basic macro/micro-nutrient things.

You also said something that struck a cord, about mathematical modeling. That's why I included the bit about variables. I know everyone is different and that in itself would skew any result, and that's beside the fact that there are so many unknowns to consider.

Quick question for you: Would you say diet science is still in its infancy? I feel like there is a lot of scientific information out there, but it seems to be a bit hodgepodge and lacking in certain areas. Like there is a lot we actually don't know.

[GringoMcGordo]

came in to say glucogenesis

Thank you. The other guy said it also but y'all have clued me into something new to learn about.

[SuffolkPunch]

Thank you! This is along the lines of what I was thinking, but you put it more eloquently that I ever could. My knowledge of biochemistry is almost non-existent beyond the basic macro/micro-nutrient things.

You also said something that struck a cord, about mathematical modeling. That's why I included the bit about variables. I know everyone is different and that in itself would skew any result, and that's beside the fact that there are so many unknowns to consider.

Quick question for you: Would you say diet science is still in its infancy? I feel like there is a lot of scientific information out there, but it seems to be a bit hodgepodge and lacking in certain areas. Like there is a lot we actually don't know.

I wouldn't say it's in its infancy, it's just that there are countless different scenarios to consider - which don't all have a have a large amount of data describing them. If you want a rundown of what we do and don't know about the science of nutrition and training, I suggest starting with Brad Schoenfeld's research and commentary.

Consider this though: Guys who don't think too deeply about nutrition science and training theory often get great results. Sometime what they do it not 'optimal' - but that doesn't stop them from getting lean and jacked.

This is because it isn't that complicated but it does take large amounts of hard work and stubbornness and consistency.

Anyone with a high work ethic can achieve the same, genetics is often used as a counterargument to this but the fact is that the vast majority of people have average genetics and any problems they have are actually down to lifestyle and habits.

[AdamWW]

I wouldn't say it's in its infancy, it's just that there are countless different scenarios to consider - which don't all have a have a large amount of data describing them. If you want a rundown of what we do and don't know about the science of nutrition and training, I suggest starting with Brad Schoenfeld's research and commentary.

Consider this though: Guys who don't think too deeply about nutrition science and training theory often get great results. Sometime what they do it not 'optimal' - but that doesn't stop them from getting lean and jacked.

This is because it isn't that complicated but it does take large amounts of hard work and stubbornness and consistency.

Anyone with a high work ethic can achieve the same, genetics is often used as a counterargument to this but the fact is that the vast majority of people have average genetics and any problems they have are actually down to lifestyle and habits.

Exactly this... people often forget our bodies are not a closed, controlled system.

You can attempt to control all you can, but it’s impossible to treat our circumstances like a computer program with precise inputs and outputs... we’re just not that capable

Also, many of the tiny details only become more critical when you’ve already eeked out the vast majority of your progress into the advanced stage, and by then you’d already have made considerable progress regardless of the program / method you follow.

[kingofturtles]

Also, many of the tiny details only become more critical when you’ve already eeked out the vast majority of your progress into the advanced stage, and by then you’d already have made considerable progress regardless of the program / method you follow.

80/20 rule.