There are quite a lot of nutritional stuff out there which do not taste great - some sort of gluey stuff which has all the vitamins and things you need, maybe made from some thing like spirulina or suchlike.
My idea is to take a lot of such stuff in a reservoir carried in a backpack and introduce
it directly into a suitable point within the human alimentary canal. If we must avoid surgery it can be a tube down the throat - no, that will interfere with speech, so it has to be a tube up the other end, reaching up into the stomach or maybe just below it (add the acids to the food directly).
So your food, or the vast bulk of it, will be delivered to your backpack in suitable refills and while you are at it, you can insert another tube to take away the waste - before the large interstine, so that the thing is still semi-solid. Drink lots more, to account for the wasted water. And at the time the refills are delivered, the empties can be shifted over to be filled with the waste, and the full waste bins taken away.
So you can eat all the junk food you want - or items with taste but no nutrition, like flavoured paper pulp shaped into pretty things and labelled with pretty names.
Why? Isn't the present scheme of sitting with a bunch of cronies around a table, and selecting things, and shoving them into your mouth, and chewing them with teeth most expensively reworked, and swallowing, et al, good enough?
Aye. But think of the time this will save, and the nice techy feeling of being the only one with the brand new UAFS (Up Arse Feeding System)