Sunday, June 19, 2011

You Don't Want to Gain Muscle? Then You'd Better Avoid Animal Protein. Additional(!) 200g of Pork a Day Build Lean Mass and Improve Blood Lipids and Glucose Levels.

Image 1: I don't know about the barbecue
sauce, but without it, this lean pork fillet
would be a healthy muscle builder
(image by Wikipedian Kbh3rd)
"Meat is unhealthy!", "Muscle is unaesthetic!" and "I don't want to look like a man!",  if you recognize your own line of thinking in these statements, you probably are a women and certainly not a regular visitor of the SuppVersity. In that case, it is even more important for you to go on reading about the impressive results an investigation (Petzke. 2011) into the purported negative effects increased meat consumption may have on previously healthy young women.

Klaus J. Petzke and his collegues from the German Institute of Human Nutrition in Potsdam-Rehbruecke, Germany, recruited fourteen female subjects among the students of the Intitute of National Sciences in Potsdam and randomized them to one of two groups:
  • Group 1, the meat-eaters (M), were advised eat additional 200g of lean pork meat (fillet) to their diet (the scientists demanded that the fillet was eaten separately from their usual meals, in order to make sure that the condition of "additional" meat intake would be met).
  • Group 2, the no-meat-eaters (NOM), were instructed to abstain from consumption of all meat and meat products, but were allowed to consume eggs and dairy.
The cross-over design of the study demanded that after the initial 4 weeks, participants who had initially been assigned to the meat-eater group (M) switch to the no-meat-eater (NOM) group for another 4 weeks and vice-versa.
Figure 1: Changes in macronutrient composition [in g/day] in the meat-eater (M) and no-meat-eater (NOM) groups
(data adapted from Petzke. 2011)
As the data I plotted in figure 1 shows, the the macronutrient composition of the diets changed in the course of the dietary intervention in both groups. With an increase in both protein and fat intake, the meat-eater group raised their overall daily caloric intake by 180.4kcal/day, while the members of the no-meat-eaters (NOM) reduced their overall caloric intake by - 97.6kcal/day. That being said, the degree of self-imposed calorie and prescribed & self-imposed macronutrient modulation (from 17% protein, 32% fat, and 51% carbohydrate at baseline to 25%, 33%, 42% in the meat-eaters and 14%, 33%, 53% in the no-meat-eaters) was by no means as radical as their counterparts in many of the currently propagated diet programs. Consequently, the absolute effects on body composition, in general, and weight loss/gain, in particular, were negligible (something that may come as a surprise to those among you and/or your, probably female, friends who assume that protein makes you big and bulky). What is of greater significance, anyways, are the trends that become observable:
  • Both groups had the same absolute amount of weight change, but the meat-eaters gained 300g, while the no-meat-eaters lost 300g of body weight [note: this difference had statistical significance with P<0.05].
  • In both groups the weight changes affected solely the amount of lean body tissue.
So, after all, the addition of 50g of protein, equivalent to about 200g of lean port or 2x 30g scoops of whey protein, to the diet effectively increased lean muscle mass in a real world scenario without exercise intervention. And it did so without detrimental effects on the young women's health. Other than the scientists had expected, the increase in animal protein (+100% compared to baseline and +180% to no-meat-eater group) did in fact have beneficial effects on both blood lipids and glucose levels (cf. figure 2)..
Figure 1: Changes in Blood lipids in meat-eaters and no-meat-eaters in the course of a 4 weeks dietary intervention.
(data adapted from Petzke. 2011)
Even according to the current mainstream paradigm, a substantial decrease in total and LDL cholesterol with only a slight dip in HDL that is accompanied by decreased triglyceride and glucose levels can hardly be (mis-)interpreted in favor of the "red meat is bad for you"-hypothesis - after all, pork fillet is red meat, and I want to add unprocessed! red meat. Ah, and before I forget: I doubt any of the girls looked bulky with those 300g of additional muscle on her frame ;-)