Seasoned air travelers know that jet lag after flying east is far tougher than that due to flying west. The reason for this that the human body clock can adjust more easily to an extended day than to a shortened day. Scientists say that the body clock can adjust for up to two hours of extended day (caused due to flying west) in 24 hours but can only adjust for a one hour of shortening of the day (caused due to flying east).
Taking melatonin pills at bedtime at the destination and exposure to sun-light mimicking “happy lights” in the mornings before flying from home can prove helpful for reducing the effects of jet lag for travelers flying east.
Read more about the science of jet lag at WaPo:
Jet lag is tougher when traveling east, but precautions can ease its effects