The obesity invariably associated with some high-fat diets is caused by an absence in these diets of certain nutrients that are necessary for an active metabolism, not by excessive caloric intake
Hence, people on these high-fat diets do not consume too many calories
The disorientation observed in airline pilots after transoceanic flights is caused not by sleep deprivation but by disruption in their exposure to daylight. Hence, transoceanic pilots do not suffer from sleep deprivation.