According to NASA, you need one day for every one-hour time zone crossed to regain normal rhythm and energy levels. So a 7-hour time difference means it will take seven days for you to feel back to normal again.
Most of us can't afford a day of disorientation, let alone seven, and there are several things you can do to help lesson the impact of jet lag:
Drink water: lots of it!
The air on board an airplane is very dry, which leads to soar throats, dry skin, chapped lips, etc. In addition to making you look haggard as you de-board, dehydration compounds the effects of jet lag. Drinking water will help, and coupled with the application of your favorite lotion, you'll be looking and smelling better than those around you—especially if you've kept them up with frequent trips to the bathroom.
Avoid booze and coffee while on board.
Let's be honest, airplane coffee never tastes that good anyway.
Exercise any way possible while on board.
Be creative: rotate your ankles, flex your buttocks while seated, do small stretches while waiting in line for the restroom, or even use exercise as your excuse for frequent visits to that cute guy sitting in seat 31A. Note: heightened security measures onboard make joining the mile high club an unadvisable exercise option.
Get plenty of sleep
Sleep the night before your flight, and don’t fool yourself into thinking that you’ll catch up on sleep while on the plane: this doesn’t happen.
Hit the showers!
If you have a connection where showers are available, by all means take one. This will freshen you up and help with circulation. When you arrive to your destination, put "take a refreshing shower" at the top of your to-do list.
Spend some time every day outdoors.
Set your watch to local time, and eat and sleep according to local time. We've all traveled with those people who seem constantly fixated on "what time it is back home." These people have a tough time adapting their sleeping and eating schedules to the local time.
Do not underestimate the effects of jet lag.
It can make you feel uncomfortably sluggish and perhaps even a bit depressed. Keep yourself busy and active during the day, and at night make yourself as comfortable as possible and do your best to get 8 hours of sleep.