Ryzel asked Layton Lewis to eat already, but Layton insisted on eating only after he tried every dish. So, Ryzel tried every dish on the table for Layton to be assured and start eating.
In the current interstellar era, there are various types of food from different planets, but the guides, who have relatively low-level physiques, cannot eat the majority of them.
With a level A to level SSS physique, sentinels can destroy some zergs with just their strength alone. They are also immune to diseases and viruses, allowing them to travel without fear of contracting an infection. So, of course, they can also eat anything, even if it's poisonous.
With a level C to level B physique, common people are already considered strong as they can already carry five hundred kilograms (500 kg). They can also eat almost everything, as long as it's not poisonous.
