Thursday, January 13, 2011

Protein Cycling Diet

Background: I've followed Perfect Health Diet (PHD) for some time now. Not to lose weight - as I was left out looking pretty emaciated after last summer's foolish raw vegan experiment - but to gain (muscle) weight.

I'm happy with the results so far. I'm probably ready to tackle Step Four of the book now, which is about preventing disease.

In chapter 'Eleven Ways To Enhance Immunity', 'The Sixth Way: Restrict Protein' mentions autophagy.
"Protein restriction benefits intracellular immunity in two ways: (1) It cooperates with the body's intracellular immune strategy of depriving bacteria of amino acids... (2) Reduced protein intake promotes lysosomal autophagy, which kills bacteria and viruses."  
So what is autophagy? Autophagy contributes to the clearance of damaged organelles and aggregate-prone proteins, and thus supposedly to longevity. Defective autophagy has been scientifically connected to many human diseases including cancer, myopathies, and neurodegeneration including Parkinson’s, Alzheimer’s, etc.

PHD explains 'Protein Restriction, Autophagy, and Longevity' this way:
"One mechanism by which protein restriction extends lifespan is by promoting a recycling process called autophagy. Proteins generally become useless after a time: they fold into the wrong shape, or they glycate with sugar, and no longer work. These 'junk proteins' gather in cells until a cleanup mechanism, autophagy, is triggered. When protein is scarce, cells turn on enzymes that digest junk proteins, recycling their amino acids. This cleanup improves cellular health. Autophagy is necessary for protein or calorie restriction to extend lifespan."
PHD also adds this piece of advice about the benefit of muscles:
"Resistance exercise, which redirects protein toward muscle, helps deprive pathogens of amino acids. More importantly, it creates a protein reserve; muscles can be catabolized if needed to avert protein deficiency. Thus, resistance exercise makes low-protein diets safer."
I've probably done enough resistance training during the past months to create sufficient muscle reserves.

I found it interesting when PHD blogged:
"In a recent comment, gunthergatherer introduced me to an e-book by Ron Mignery suggesting alternate-day protein elimination (a “protein cycling diet”) as an autophagy-promoting practice that should help prevent neurological disorders. This is a variation of our protein restriction, fasting, and ketogenic dieting techniques, all of which are designed to promote autophagy. Autophagy is the key intracellular immune mechanism that protects against bacterial and viral infections. It is good to see that other people are developing the same ideas we are. Hopefully these ideas can spread beyond a few scientist-dieters into general practice."
So I decided to explore this a bit further.

Protein Cycling Diet is a knol (a Google project that aims to include user-written articles on a range of topics) by Ron Mignery. This is basically how it is supposed to work:

(1) Calculate the rate of cleaning by autophagy:
  • a 70 kg male (that's me) requires about 25 g of protein per day to meet protein synthesis needs.
  • Cell contents account for ⅔ of body weight.
  • Body is about 17% protein by weight.
  • 70 kg x 17% x ⅔ = 8000 g of cell protein.
(2) When autophagy is induced by protein starvation, the body will conserve let's say 20%, so at least 20 g per day of protein must be recycled:
  • 20 g / 8000 g = 0.25% per day recycled.
  • That value supposedly exceeds the rate of accumulation of aggregates, so in theory a neurodegenerative (and possibly also many other) diseases can be prevented.
  • Measured values in studies have been larger than 0.25% per event, but 0.25% is the best educated guess for the actual value in human neurons, as the body will sacrifice some muscle tissue to provide amino acids to the brain.
(3) Aim for 1-3 x 24h periods (18h might do it?) a week of protein restriction:
  • Anything less than 7% of calories (human milk level) should be sufficient, especially as protein digestion is not 100% efficient.
  • Fats and carbohydrates are not restricted, so those can and should be eaten. As Perfect Health Diet says: "Protein intake of 200 to 600 calories per day seems to be a healthy plateau range if sufficient carbs are eaten, but the plateau range becomes much narrower - a window around 500 to 600 calories - if carbs are restricted." 
  • Protein Cycling Diet seems a lot like Alternate Day Caloric Restriction diet, except you get to cheat with carbs and fats. Caloric restriction or intermittent fasting does not seem to be necessary for autophagy to happen. Still it might be a good idea to throw in a random caloric restriction/intermittent fasting period. 
  • For example, one might skip protein in the evening and next morning, or whatever suits your schedule best. It would still be possible to eat 50-150 grams of protein every day during the unrestricted periods, resulting in the 200-600 cals mentioned above.
  • Low-protein foods include for example: most fruits (except apricots, blackberries, cantaloupe, gooseberry, lime, nectarines, oranges, peaches, raspberry, strawberry, watermelon, and white grapefruit), carrots, and whipping cream. 
  • In case one would feel tempted to consider eating fruits, the lowest fructose fruits would be clementines (1640), pink/red grapefruit (1770), pineapple (2120), tangerines/mandarins (2400), honeydew (2960), and plums (3070). These seem too high-fructose to safely eat in any substantial quantities, so that would leave us with olives, avocados and a squeeze of lemon juice.
I've actually already experimented with Protein Cycling a little, but I'm not sure if it's worth continuing further. I'm not sure it would work very well for me.

In any case I'll also keep on skipping a meal occasionally, as I'm used to doing that. Intermittent fasting seems like a much more appealing and natural approach at the moment.


Woody said...

While some of this occures in a total fast wouldn't the higher
growth hormone levels asociated
with fasting cut your protein requirements ? I also wonder how
much of this junk could be recycled
in a week of still consuming some
calories but no protein?

Trail Plodder said...

Excellent questions. You are probably on to something.