re: 4-5 continents in 2-3 weeks

I find it easier to head east rather than west....another tip is to set your watch to destination time immediately upon boarding. Two meals a day, rather than three, might also help. A larger, later breakfast in lieu of lunch, then a light snack on days when you know you have big business dinners...I'd also bring along a supply of your favorite dried fruits, nuts, protein bars, other shelf stable stuff so when you get the munchies at odd hours, you can eat. Higher fiber food choices are good as well (apples, for example).