Your recommended eating window is when Arcashift predicts your body is most ready for food. Circadian rhythms cause your metabolism to fluctuate during the day, making you more or less prepared to handle food at different times.
Try to keep most of your big meal intake during your recommended eating window in Arcashift. Note that if you’re only doing one-off night shifts, your eating window may not overlap much with the hours you’re awake. The more night shifts you do, the more your eating window will probably come to overlap with the hours you work—but until that happens, aim to keep snacking outside the meal window to a minimum.