Wednesday, October 9, 2013

Protein Requirements of Dieting Strength Athletes: More is Better Only in the Presence of Adequate Carb & Fat Intake. Optimal Muscle Retention With 2-3g/kg Lean Body Mass

Believe it or not: Being lean, athletic and well-conditioned is a disqualifier, when it comes to "body recomposition" (=building muscle +  losing fat at the same time). Simply upping your protein intake indefinitely is not going to change that..
This is one of those article, where I thought twice whether or not it would be worth writing. If I knew that the majority of you had full-text access to the recent review by Helms, Zinn, Rowlands and Brown, I would probably stick to a couple of comments on my Facebook page and suggest you read the whole paper, yourself.

In view of the unfortunate fact that research is not really a public good, and full-text access is very limited unless you work / study at a University, this would leave most of you with nothing but a conclusion to an abstract that could could easily be misinterpreted in a simplistic: "More is better!" way; a conclusion you would obviously revise, if you had the change to read the whole paper which does have more to offer than two random numbers.

Apropos "random": In view of the fact that Helms et al. found only 6 studies that provided (in some cases limited) information about the influence the amount of dietary protein will have on lean mass retention and fat loss in strength trainees, neither the numbers in the headline nor ostensibly more accurate figures Helms et al. provide are more than a brought guideline. The "true" optimum and in my humble opinion even the question whether such a thing has yet to be found.

I: Energy-, not protein-intake is the main determinant of muscle loss

The 2011 study by Garthe is only one of many studies that confirms that a lower calorie deficit will yield better dieting results (i.e. greater fat and lower lean mass loss); results after 8.3 (19% deficit) and 5.3 (30% deficit) weeks (Garthe. 2011)
What is more or less indisputed and at the same time one of the most important, because often overlooked, or I should say "willingly ignored", determinants of lean mass loss is the fact that
"[...] the magnitude of the caloric deficit imposed is likely one of the most powerful variables that impacts FFM loss, potentially being more important than protein intake." (Helms. 2013)
In other words, the "harder you diet", i.e. the more severe your caloric deficit, the more lean muscle you're going to lose. This appears to be self-evident, I know, and yet the average and not so average dieter (e.g. the bodybuilder who comes in not just flat, but actually small) tend to forget about it.

II: Body recomposition is something for the "fat beginner"

Next to hitting it too hard, being in denial is probably the most common threat to your dieting success - in denial of the fact that such a thing as "body recomposition", i.e. concomitant loss of fat and increase in muscle mass is a prerogative of the chubby beginner.

Suggested Read: "Seven Meals/Day, More than 800g of Carbs & 1000kcal Over Maintenance and Still Lean Gains!" | read more
Based on studies by Peterson, Rhea, & Alvar (2005) and Garthe et al. (2011) Helms et al. rightly point out that gaining lean mass while being on a caloric deficit is not the norm, but rather the exception; an exception that will occur almost excursively in to novice lifters and among those most probably in the chubbier ones, who can draw on larger body fat reserves while they are dieting. In "leaner more experienced weight lifters", on the other hand, "it may be unrealistic to expect a lack of FFM loss or FFM gain in leaner" (Helms. 2013)

The common, though schizophrenic approach to fat loss that denies the inevitability of lean mass losses is thus more often than not going to fail you; and if you are still wondering why your abs don't shine in full glory, ask yourself if the reason may not be your own fear afraid of losing muscle that you never diet long or hard enough to attack the stubborn fat.

III: When you eat so much protein that there is no room for fat and carbs bad things happen

While it is correct that your body can use protein as an energy source, forcing it to do just that by consuming so much protein that the amino acid chains constitute the lion's share of your daily energy intake is going to have significant detrimental effects on your dieting success. As Helms et al. point out...
  • consuming a high protein diet with very little carbohydrate in it is going to hamper your exercise performance (Walberg. 1988), while
  • consuming a high protein diet with too little fat in it is going to have negative effects on your mood and emotional stability (Mettler. 2010).
Unfortunately, it is difficult to determine the exact "minimal requirements" of these nutrients. Until now, these have not been explicitly studied and in view of the scarcity of existing research (remember: N=6!) it is almost impossible to extrapolate them from the data we have.
Ketogenic diets are not high in protein: Please note that the previously mentioned detrimental effects of low carbohydrate intakes will only arise in a high protein context- The latter is preventing you from transitioning into full ketosis and deriving the corresponding benefits. A ketogenic diet cannot be "high" in protein; and it is save to assume that the risk of being kicked out of ketosis is specifically high with fast digesting and highly gluconeogenic protein sources like whey (cf. Calbet. 2002).
If we take a look at the data we have it does yet appear that 20% is the absolute minimum for fat and ~30% could be the minimum for carbohydrate intake in a high protein diet scenario.

In this context Helms et al. do actually cite a study, every SuppVersity reader should be familiar with: The recently published metabolic ward study by Pasiokos et al. (read the previous SuppVersity article).
Figure 1: Change in body composition and protein synthesis (Pasiakos. 2013)
The results of this study would support the hypothesis that increasing your protein intake from 1.6g/kg body mass to 2.4g/kg body mass so that the carbohydrate intake drops to ~20% of the total energy intake, will accelerate the overall loss of body mass at the expense of lean muscle tissue.

Meanwhile it should not remain unmentioned that these effects were observed in a "low" intensity training scenario that did not provide for a maximal exercise-induced stimulus of protein synthesis. The hypothesis that a more hypertrophy specific training program would have yielded very different outcomes is however questionable and - as of now - just as the term "hypothesis" implies hypothetical.

IV: Athletes should use their lean lean body mass to determine their protein intake

Within the bodybuilding community it is actually common practice to prescribe (often hilariously high) protein intakes on a "per kg of lean mass" or "per lbs of fat free mass" level. Among recreational fitness enthusiasts and eve among scientists this is however still the exception; and that despite the fact that this practice has the advantage that it will (automatically) yield higher per kg total body mass protein intakes for leaner athletes. This "scaling" approach is in accordance with Helms et al.'s conclusion that
"[a]thletes with a lower body fat percentage, or a primary goal of maintaining maximal FFM should aim towards the higher end of [he protein intake range, while t]hose who are not as lean, or who are concerned primarily with strength and performance versus maintenance of FFM can safely aim for the lower end of this recommendation." (Helms. 2013)
I guess by now you are probably asking yourself what on earth the "exact" recommendation of the scientists are, right? Well, I guess it's time to let the cat out of the bag, then ;-)
How do dermine your "optimal" macronturient intake? The easiest way to go is to (1) use your regular daily energy intake (i.e. the amount of energy you consume when you are weight stable) subtract 20-30%. Then you take the result and (2) subtract the 450kcal energy equivalent of your 50g minimal fat intake and (3) 2.8 x 4kcal/kg x lean body mass, the energy equivalent of your protein intake. Lastly, you (4) divide the rest (baseline - fat - protein) by 4 kcal/g and have your daily carbohydrate allowance in grams.
Example? Easy! Baseline intake: 2500kcal, (1) 20% calorie reduction → 2000kcal, (2) subtract 50g fat * 9kcal/g → 1550, (3) subtract 2.8 x kcal/kg x 65kg lean mass → 822kcal (4) divide this value by 4 and get your carb intake, here 205.5g. Your overall macro ratio would thus be 182g of protein, 205g of carbs and 50g of fat.
This ratio would be adequate for athletic and active individuals, while sendentary and/or insulin resistant obese indivuals may in fact consider turning this into a low carb diet, by reversing the fat and carb intake.
What's the optimum, then? According to Helms et al. the "optimal" protein intake for strength athletes on a energy restricted diet amounts to 2.3-3.1g/kg of the athletes fat free mass. The latter includes both muscle, as well as organ mass and body water and will - as I have pointed out in IV. make sure that athletes with lower body fat mass will consume more protein than the chubby beginner who has just taken up weight lifting to prepare for spring break.

Let's just briefly check what this may mean for you, a young man / women with 12% or 19% body fat and a body weight of 80kg or 60kg, respectively. While his protein intake would be ~161-217g, her protein intake would be "only" 112g-150g per day. If we now assume that the daily energy intakes of the two are 2,000 and 2700kcal per day (for maintenance) and that both follow my suggestion to reduce their calorie intake by only 20%-30%, this would leave ~1,300kcal (male example) and 980kcal for carbs and fat (woman). If we further prescribe a minimum intake of 50g of fat (this would be more than the afore-cited 20%, but is imho a sane minimum intake) this would leave us with ~210g of carbs for him, and 130g of carbs for her - both not exactly bad macro-ratios for an active individual whose main intention is to shed some body fat. If you end up with way more than 200g of carbs and/or are insulin resistant consider cutting the carbs back to 200g or below (insulin sensitive, but not very active), or 150g or below (insulin resistant, but not obese).
References: 
  • Calbet JA, MacLean DA. Plasma glucagon and insulin responses depend on the rate of appearance of amino acids after ingestion of different protein solutions in humans. J Nutr. 2002 Aug;132(8):2174-82.
  • Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. Int J Sport Nutr Exerc Metab. 2011 Apr;21(2):97-104.
  • Mettler S, Mitchell N, Tipton KD. Increased protein intake reduces lean body
    mass loss during weight loss in athletes. Medicine and Science in Sports and Exercise. 2010;
    42(2), 326-337.
  • Pasiakos SM, Cao JJ, Margolis LM, Sauter ER, Whigham LD, McClung JP, Rood JC, Carbone JW, Combs GF Jr, Young AJ. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J. 2013 Jun 5. [Epub ahead of print]
  • Peterson MD, Rhea MR, Alvar BA. Applications of the dose-response for muscular strength development: a review of meta-analytic efficacy and reliability for designing training prescription. J Strength Cond Res. 2005 Nov;19(4):950-8. Review.
  • Walberg JL, Leidy MK, Sturgill DJ, Hinkle DE, Ritchey JS, Sebolt DR. Macronutrient content of a hypoenergy diet affects nitrogen retention and muscle function in weight lifters. International Journal of Sports Medicine. 1988; 9(4), 261-266.