Lunch breaks don’t work this way. For my IT jobs I was scheduled 8-5, which included an hour off for lunch. So that’s “working” 8-12(4 hours) and then 1-5(4 more hours). If an employer officially got rid of lunch then they’d need to schedule me from 8-4 or 9-5 to keep me at a scheduled 8 hours a day. Which frankly I’d rather work those hours anyway.
Now they could just do the 8-5 schedule and social pressure you into not taking your lunch break, but there’s nothing stopping them from doing that anyway. All they have to do is cater food to their employees(order in pizza), which happens during crunch times at certain places anyway.
Soylent really isn’t changing anything here.