You wouldn’t go into a meeting without your lies and evasions in order, right? Toe the line at a marathon with just your left shoe on? Hell no, you say. But tell us: Why do you step out the door on the most important days of your life with any old swill in your stomach?

Guilty as charged, right? The thing is, a nutritional edge is such an easy advantage to claim. Your premeeting, pregame, pre-bacchanalia foods can bring mind and body in tune, and supply you with fuel that will sustain you through the last Power Point, the final fit with the caddie, the last snog in the corner.

To help you find that edge, we consulted a team of Machiavellian nutritionists and tactical snackers to determine the absolute best foods to send you into the fray and welcome you home. On your mark, get set, eat.

When You’re Playing Catch-up at Work

You’ve spent the last 3 days cruising the Internet and napping in an empty third-floor office, but now you’ve got to produce.

* Eat: Small meals with snacks in between. Start the morning with a low-fat blueberry muffin and a cup of whole grain cereal with low-fat milk. An hour or two later, grab an ounce or two of cheese and a banana. At noon, go Chinese — chicken or vegetable stir-fry and steamed rice is ideal. In the afternoon have more snacks: an orange at 2, and a pack of peanut-butter cookies or a bag of nuts at 4.

* When: Try to eat once every 2 hours.

* Why: Frequent snacking prevents the dips in blood sugar that lead to Brian Wilson-like lulls in productivity. “Large meals trigger a surge of energy-sapping insulin, but small meals help to keep insulin and energy levels at their peak,” says Jackie Berning, a University of Colorado nutritionist.

* Avoid: Too much protein without carbs to counterbalance it. Since your brain runs on carbohydrates, you need a steady supply in order to perform at your peak.

After Your Workout

When you’re not savoring the pump or preening by the water fountain…

* Eat: An energy bar with a four-to-one ratio of carbohydrates to protein and a big glass of water. A chocolate-chip Clif bar has a perfect ratio of 40 grams of carbs to 10 grams of protein.
* When: As soon as you finish your last rep

* Why: The minutes following a workout are the easiest time to replenish your carbohydrate reserves. And the four-to-one ratio of carbs and protein is ideal for triggering a spike in your body’s production of insulin. “Having extra insulin in your system after working out stimulates protein synthesis, making your body’s muscle-building system more effective,” says Thomas Incledon, director of sports nutrition for Human Performance Specialists.

* Avoid: Calorie-dense protein shakes. Drink 1,500 calories after burning 1,000 calories and you still gain weight.

When You Have a Tee Time

John Daly can drive the ball 350 yards after eating Taco Bell food, but you’d better hope you’re not downwind in the gallery. Instead of going Mexican, you should…

* Eat: A cup of low-fat yogurt and 2 tablespoons of peanut butter on a slice of whole wheat bread

* When: 1 to 2 hours before tee time

* Why: “The yogurt and peanut butter provide 20 grams of protein, which will slow digestion and keep your energy levels high for an entire round of golf,” says Roxanne Moore, a nutritionist at Towson University.

* Avoid: A pre-greens pizza feast. “Spices and tomatoes can trigger an upset stomach,” says McMurray.

Before a Marathon

Try to sneak a bite of whatever the Kenyans are eating. But if they won’t share…

* Eat: An energy bar and a large glass of water

* When: Half an hour before race time

* Why: The carbs will give you the energy you need to make it to that last mile.

* Avoid: Skipping breakfast. Eat an egg and a small bowl of oatmeal, and drink a cup of low-fat milk.

During a Long Bike Ride

You can pack your bag with hard-to-swallow sports gels, or you can go for something a bit closer to real food.

* Eat: Dehydrated fruit, low-fat granola bars, and Fig Newtons

* When: At the bottom of that next grueling hill

* Why: “You need to keep your energy up and stay hydrated,” says Robert McMurray, a professor of sports nutrition at the University of North Carolina. “Fruit and granola are ideal.”