I don't think anyone needs to eat as much as 3,500 calories per day in order to grow muscle. You can grow fat on that number, but there is nothing that suggests that your muscle volume will increase.
Everyone has their physiological limits, the plateau that they will inevitably hit due to normal human growth capacity. Some will find that genes dictate how much they grow, while others will defy the laws of physiology by introducing steroids and growth hormone into the mix.
Naturals reach their limits after various years of training and proper dieting. They then graduate into hormone use and slowly, but surely will reach their limits as well. Those that push too hard, could end up causing problems for themselves. After all, there is only so much the human heart can sustain.
Hopefully, one of our resident experts in human physiology can chime in on this.
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