Protein needs and P-ratio

[coach hale]

The popular fitness literatute rarely (if ever) mentions protein needs in accordance to P-ratio.

P-ratio: the fraction of total energy expenditure derived from protein when losing weight, the fraction of total energy deposited as protein when gaining weight

Payne and Dugdale (1977) The propensity to use protein as a fuel appears to be fixed in an individual regardless of whether the synthesis of protein is limited by energy or protein intake. During starvation, obese individuals appear to mobilise about 5% of total energy from protein breakdown, while normal weight subjects about 20%. Body composition exerts a profound influence on protein metabolism

Payne and Dugdale (1977) A direct relationship between protein and energy is also suggested by the P theory. During tissue mobilisation, it predicts that a constant fraction of energy should be derived from the breakdown of protein, i.e., the P ratio should remain constant. Extending this model further, I propose that the P ratio may not only influence energy balance Since the ratio FUNL/BMR has been shown to be constant in an individual, the allometric relationship reported here between FUNL/BMR and ONL suggests that all three parameters are closely connected and bear a physiological relationship to one another. It is therefore proposed that subjects with a low P ratio (i.e., the obese) will not only have a lower FUNL but also a smaller ONL and hence a lower protein requirement.

notes: FuNL (fasting unrinary nitrogen loss)
BMR (basal metabolic rate)
ONL (obligatory nitrogen loss)

P-ratio is discussed in Protein Essentials (2007 Hale). L McDonald also discusses in a couple of his books.

I am also working on a new article about P-ratio. I will be able to devote a little more time to that article once i finish the CPR Certification Myth article.

thanks
coach hale
www.maxcondition.com

[karky]

are they saying obese individuals who starve themselves burn less protein than normal individuals? Does that include protein from muscle tissue? that kind of doesn't make sense to me.

[coach hale]

That is exactly what they are saying as shown when looking at ONL and FUNL

Obese have more FFA available as well as more glycerol for gluconeogenesis

thanks
coach hale
www.maxcondition.com

[Barrett]

Well doesnt it have to do with the thermalgenitc effect that occurs when you eat protein?? (SORRY FOR THE SPELLING)

[coach hale]

What you are thinking about is the TEF (thermic effect of feeding). It is with protein than it is with carb or fat

Once again as shown with ONL or FUNL people with higher p-ratio see more loss of nitrogen. It might make more sense if you understand what happens when measuring ONL. Below is an excerpt from Protein Essentials (Hale 2007)

Obligatory protein requirements
The obligatory protein requirement is the amount of protein necessary to keep a person in nitrogen balance on a daily basis (of course this could change according to activity levels or other stresses). This requirement is determined by measuring nitrogen excretion while an individual is consuming a protein-free diet. Since nitrogen consumption is zero, all nitrogen excretion must be coming from body proteins. When measuring this value, the diet must be adequate in calories and carbohydrate intake.

The obligatory protein requirement has been estimated to be approximately 50–60 mg/kg per day, meaning a 100 kg person would lose 5–6 grams of nitrogen per day. Since protein is approximately 16 percent nitrogen, a loss of 5–6 grams would indicate a loss of 33 grams of protein per day. Taking into account digestibility issues and individual variance, a safety factor has been added to the value. This is the basis for the recommended daily allowance (RDA) for protein which comes out to 0.8 g/kg per day, which should be sufficient for 95 percent of the population to maintain nitrogen balance. The RDA assumes high quality protein intake and adequate energy consumption. RDA values can also vary between age groups. Another thing to consider is that RDA values were never meant to be applied to active individuals (much less bodybuilders and competitive athletes).

thanks,
Coach Hale
www.maxcondition.com

[coach hale]

sorry i forgot a word

It is higher with protein than carb or fat

thanks
Coach Hale
www.maxcondition.com