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Thermic effect of carbs vs proteins

Posted: Tue May 03, 2011 6:19 pm
by hoosegow
I'm hoping some of you smarter members can help verify what I think I learned today. The thermic requirments (energy to process) is roughly double for protein than it is for carbs (See the protein debate stickie). This got my curiosity up. The general rule of thumb (from looking at various other web sites) then is 30% of the calories to digest protein is lost due to the process. Thus 15% would be needed for carbs. So if I'm understanding this correctly:

300 calories of protein, you net 210 calories of energy.
300 calories of carbs, you net 255 calories of energy.

Does this seem right?

Re: Thermic effect of carbs vs proteins

Posted: Tue May 03, 2011 7:01 pm
by NightFaLL
hoosegow wrote:I'm hoping some of you smarter members can help verify what I think I learned today. The thermic requirments (energy to process) is roughly double for protein than it is for carbs (See the protein debate stickie). This got my curiosity up. The general rule of thumb (from looking at various other web sites) then is 30% of the calories to digest protein is lost due to the process. Thus 15% would be needed for carbs. So if I'm understanding this correctly:

300 calories of protein, you net 210 calories of energy.
300 calories of carbs, you net 255 calories of energy.

Does this seem right?

That's a fairly good estimation from what I understand. Why does this pique your curiosity?

Re: Thermic effect of carbs vs proteins

Posted: Tue May 03, 2011 7:06 pm
by ironmaiden708
Yep, that sounds about right. Will have variance based on source (ex: whey vs. steak)

Re: Thermic effect of carbs vs proteins

Posted: Tue May 03, 2011 7:16 pm
by NightFaLL
Just to add, as well, fat has about 2-3% TEF from what I've read.

Re: Thermic effect of carbs vs proteins

Posted: Tue May 03, 2011 7:24 pm
by Kenny Croxdale
hoosegow wrote:I'm hoping some of you smarter members can help verify what I think I learned today. The thermic requirments (energy to process) is roughly double for protein than it is for carbs (See the protein debate stickie). This got my curiosity up. The general rule of thumb (from looking at various other web sites) then is 30% of the calories to digest protein is lost due to the process. Thus 15% would be needed for carbs. So if I'm understanding this correctly:

300 calories of protein, you net 210 calories of energy.
300 calories of carbs, you net 255 calories of energy.

Does this seem right?
The Thermogenic Effect of Food
http://www.associatedcontent.com/articl ... html?cat=5

Fats

Approximately 3% of the calories consumed from fats are needed to digest them.

Carbohydrates

About 7% of the calories from carbohydrates are utilized for digestion.

Protein

An average of 27% of the calores from protein are requiered for digestion.

Kenny

Re: Thermic effect of carbs vs proteins

Posted: Tue May 03, 2011 9:05 pm
by hoosegow
NightFaLL wrote: That's a fairly good estimation from what I understand. Why does this pique your curiosity?
Just curious. I call it going down the rabbit hole. You read one thing, it leads to another, etc.

Thanks guys. I just wanted some confirmation on my understanding.

Re: Thermic effect of carbs vs proteins

Posted: Wed May 04, 2011 2:44 am
by Jungledoc
This reminds me of an old Burns and Allen show. A salesman was showing Gracie a wholesale appliance catalog and telling her about the discount he could get for her.
"I can save you 20% on this refrigerator".
"OK, I'll take one."
"I can save you 15% on this stove."
"OK, I'll take one."
"I can save you 10% on this washer."
"OK, I'll take one. Let me know as soon as I've saved enough to pay for it all."

Re: Thermic effect of carbs vs proteins

Posted: Wed May 04, 2011 9:21 am
by hoosegow
Dang rabbit hole.

Okay so if I'm looking for some quick energy before a workout, I eat a pack of Twizzlers - for the sugar and their magical properties. Since oils are more efficient, would it be better to guzzle a couple of tablespoons of olive oil, or are sugars absorbed in the stomach and fats in the intestines? Or do sugars, though less efficient, absorb quicker than fats due to their hydrophobic tendencies and relatively long chains?

Re: Thermic effect of carbs vs proteins

Posted: Wed May 04, 2011 2:34 pm
by NightFaLL
hoosegow wrote:Dang rabbit hole.

Okay so if I'm looking for some quick energy before a workout, I eat a pack of Twizzlers - for the sugar and their magical properties. Since oils are more efficient, would it be better to guzzle a couple of tablespoons of olive oil, or are sugars absorbed in the stomach and fats in the intestines? Or do sugars, though less efficient, absorb quicker than fats due to their hydrophobic tendencies and relatively long chains?
Everything I've read says that fats do nothing to improve athletic performance pre/peri workouts.

Plus, as you're a huge guy already, I'd say the twizzlers are working and from an energy standpoint, they're going to be better utilized during weight training.

Re: Thermic effect of carbs vs proteins

Posted: Wed May 04, 2011 4:04 pm
by ironmaiden708
hoosegow wrote:Dang rabbit hole.

Okay so if I'm looking for some quick energy before a workout, I eat a pack of Twizzlers - for the sugar and their magical properties. Since oils are more efficient, would it be better to guzzle a couple of tablespoons of olive oil, or are sugars absorbed in the stomach and fats in the intestines? Or do sugars, though less efficient, absorb quicker than fats due to their hydrophobic tendencies and relatively long chains?
Just because the body requires less energy to digest doesn't mean that it is the best preworkout energy source. Carbs still requires less steps to get to a usuable form. The body basically emulsifies fats in bile which takes hours. Carbs are digested via enzymes (lactase, maltase, etc) and can be absorbed in minutes. Neither are digested or absorbed effectively in the stomach. Proteins are more or less predigested in the stomach though, the acidic environment denatures the proteins.

That info is very general, there are many more factors which affect digestion/absorption of macros.

Re: Thermic effect of carbs vs proteins

Posted: Wed May 04, 2011 7:57 pm
by hoosegow
Have I told you that I'm glad you're back posting?

Re: Thermic effect of carbs vs proteins

Posted: Thu May 05, 2011 11:26 pm
by ironmaiden708
Hah... I think you might have but thanks