In the United States - anyway - several anabolic steroids are used in our meat industry. They include Trenbolone, Testosterone, and Estrogen. A mixture of 50/50 Estrogen and Testosterone is injected into the animal beginning at a young age. The combination has effects including better conversion of protein, water retention, and it also increases fat retention. Trenbolone is a bulking agent and is used by athletes who chose to use steroids for the same reason it is also injected into cattle because more pounds equals more profit, Testosterone is the main hormone in men, and has a number of effects ranging from aggression to larger size. I have heard, though not confirmed the estrogen is put there to deter steroid users from it. That is somewhat plausible, but so is anything cheap that increases the holy specification of "weigh in at slaughter." I want to add a couple things here that always seem to go without ever being brought to the mind of the popular collective which is, according to the “National Market Cow and Bull Beef Quality Audit — 2007, the average weight of cattle at slaughter in 1975 was 475 pounds. In 2007 it was 1,375 pounds! During that same time span the average weight of men went from 166 pounds to 195.7 pounds, and the world health organization states that 2 billion people are obese today.  

My own personal account is my own proof; I began life as a vegetarian after a family photo left me asking who the heck that person was, I was shocked to be informed the very large man was myself facing away from the camera. I weighed over 300 pounds! As I aged and bought clothes I guess I just ignored the fact the waist size kept increasing. When I stopped eating meat in 2012 I weighed 321 pounds. Within 10 months I did what no diet program could believably even think about claiming, which was losing over 140 pounds. In 2015 I began finishing my degree, and found about zero time for that pesky meal thing, and began eating meat again. I stopped in 2016 at 280 pounds.

Now a little over 1 year off meat again, I weigh 175. My energy is greater, my mind is clearer, I feel better about life, and death. When I ate meat all three of those topics were things I just avoided.