"or, through inaction, allow a human being to come to harm"
This part of Asimov's Three Laws is really poorly thought through. Humans do things to harm themselves in tiny ways many times a day, it's part of normal human life. A robot operating under the Three Laws would not differentiate between these things and more substantial harms. So, hope you like your precisely-portioned vegan diet and enforced daily exercise, along with any other lifestyle changes a robot could decide was necessary to keep you as healthy as you could possibly be. And remember, "a robot must obey the orders it is given by human beings except where such orders would conflict with the First Law," so it's not going to be listening to any attempts to command it to allow you that bacon sarnie and a pint.