And no matter how many protein shakes you guzzle down, a good diet will struggle to build any significant muscle and strength without the necessary exercise-induced physiological stimuli.
The condition isn't caused by stress or caffeine, but by the area of the brain that controls movement—and while it's rare, it can be debilitating for those who experience it.
Fortunately, people on average only compensate about 30% of the exercise-induced calorie expenditure, which doesn't seem too bad... until we look at the shockingly high variation between individual subjects.
It comes from exercise-induced muscle damage, which occurs from unaccustomed exercises, which happens to be exactly what beginners will be doing when they finally start working out.
DOMS is a symptom of exercise-induced muscle damage, which occurs unsurprisingly from exercise, but more specifically, from exercises in which one is not accustomed to performing.