I have no diet other than eat what will keep my electrolytes, vitamins, minerals, blood sugar, and blood pressure balanced. I was even specifically instructed by a cardiologist to not restrict myself. So for obvious medical reasons, I need the animal products. My parents were vegan for half a year, and during that time I was was eating a very reduced amount of animal products. My condition flared up so bad that some days sitting up in bed or showering was too exhausting. It was too hard to try and monitor my diet to ensure that I was making up for all the deficits from my parent's vegan lifestyle. I'm too lazy.
But for those *full-grown adults*
who are bulldogs about their diet choices, it seems to be a perfectly safe and beneficial diet choice. Just not a choice I could make without committing murder during a particularly violent diet-induced mood swing.