Spoken like middle management. If a knowledge worker is only putting in 4 hours they're either mismanaged or dead weight. Fire their manager and see if they are more effective, if not, then let them go. As a developer I routinely work 9 hour days without lunch and so do the others on my team and most people I've worked with as a developer. Myths like the 10% developer and lazy 4 hour knowledge workers are like the myth of the welfare queen. We really need to be more aware that when we complain about 5% of people that it becomes 100% to those outside of the field.