You only need to look at what goes in to see it's going to be full of crap UE.. battery farms etc feed highly processed (usually the carcasses of previous animals) to their livestock, packed with synthesised hormones for maximum growth. Also included are what are effectively pesticides to keep these animals from harbouring diseases,and are only kept just above "safe" food standard levels, which is a far cry from being healthy.. Not to mention they are practically swimming in their own crap.
Im afraid, as a degree holding biologist, i cant see a mechanism by which external factors such as food intake and food type can affect tissue composition.
Think about it, youre essentially saying that a man who built muscle from cheese has different muscle to a man who built muscle from beef? Doesnt sound like it makes as much sense there does it?
Biology 101 - Nutrients ingested are broken down into their component parts, in the case of proteins, amino acids, in the case of fats into fatty acids and carbohydrates into simple sugars.
Now whether or not your initial source is a lovely prime rib, or a ground up carcass, its nutritional value is a constant. The body will take in the ground up carcass, seperate out the proteins the fats the carbohydrates and the undigestible chaff. The body will break them down into their specific amino acids, sugars and fatty acids. All 'toxins', undesirable chemicals, will be filtered out by the liver or passed as waste.
The body can now use the amino acids to build muscle (which will eventually become dinner). These amino acids are 'binary' in nature, they exist in one form, one stucture and one level of 'quality'. You dont get Leucine and Good Leucine and Poor Leucine, you just have Leucine. One molecule, one structure one composition. By their very nature the building blocks are sanitized by normal biological processing.
Then you talk about hormones. Firstly hormones have little to no effect when applied orally as our livers do a damn fine job breaking them down, the dosages that 'could' be present in the tiny amount of chicken blood that MIGHT be ingested in an undercooked chicken would be beyond negligible. Hormone is not stored in muscle thus there can be no 'build up' of it over time in the chicken meat.
Its all just pseudoscience, to clarify what PSEUDOSCIENCE is, is simply something that sounds feasible to someone of good intelligence with no specialist knowledge on the subject. I totally agree that it sounds plausible that if you feed an animal junk and drugs that the resulting meat should be of questionable quality. But this is quite simply a massive underestimation of the complexity and efficiencey of biology. Millions of years of evolution have worked to combat problems like this and to assume that purely logical principles like "Crap in = Crap Out" apply is to fundementally lack a rounded understanding of biological systems