Okay, all you sensible people, thank you for your sound advice. But, now let's have the faddists' points of view, which I have taken the liberty of researching at great length and present for your edification here: follow the Atkins Diet (no carb, high protein) strictly throughout the week, the Scarsdale Diet (grapefruit and something that smells like baby urine) all weekend, supplement it with Bio-En-r-giser 2000mg tablets and mito-chondritialis powder first thing in the morning; drink loads of fennel/echinacea/mahuang/garlic/ginseng/elephantpoo tea whenever you're feeling in need of a boost and, no matter what else you do, make sure to align your running routes with the "dragon-water-paper-light" feng shui meridian - but NOT on the 7th hour of the 7th day of any month (lunar calendar, of course).
According to my research, it seems that this is the optimal way to end up looking like a well-paid Hollywood movie star for exactly 3 seasons (not including re-runs), before you collapse "from exhaustion", get a divorce, adopt a Vietnamese orphan and check into a rehab clinic of your choice.