Willpower at work!

Eat a healthy breakfast before you head out and avoid the coffee and 400-calorie muffin. For the commute, take a Thermos of coffee, fresh fruit and cereal bars. Ellen Kosowan, a registered dietitian at the Southern Alberta Institute of Technology in Calgary, suggests keeping whole-grain crackers and nuts tucked in the glove box.

Those stacks of paper sitting on your desk may be the reason you're having trouble losing weight, says Kosowan. Studies show disorganization is a major cause of workplace stress. And when you're stressed, your body secretes cortisol, a hormone that causes you to hang on to body fat. Schedule time to clear off your desk.

Some days a bag lunch just doesn't cut it. If the greasy spoon beckons, skip the burger and fries and choose a fajita with grilled vegetables. "Stay away from high-fat foods or you'll feel sluggish all afternoon," warns Kosowan. And plan your treat days: go for a slice of cheese pizza (about 150 calories and three grams of fat) with a co-worker.

That plate of cookies in your 2 p.m. meeting is tempting. But listening to your boss drone on isn't going to burn off the 100 calories every chocolate-chip cookie contains. Don't sit near the goodies; or grab something to munch on (quietly), such as a sliced apple or raisins. Offer to bring a fresh-fruit tray next time.

We all have a well-meaning co-worker who has an overflowing candy dish on her desk. But keep in mind that just five milk chocolate kisses per day can add up to a pound of extra weight a month! Avoid the candy dish or choose sweets that take longer to eat (think hard candies instead of chocolate).

Stomach rumblings often lead us straight to the vending machine when what we really need is a glass of water. Kosowan notes that we often mistake thirst for hunger, and suggests drinking a glass of water before grabbing a snack. If you must hit the vending machine, choose a cereal bar or low-fat pretzels.

In the next 24 hours you have to meet with a new client and give a presentation to your boss. But if you don't think about what you're going to eat after hours, you'll end up having chips and a pop. Instead, take 15 minutes to grab a bowl of soup or a salad from a takeout place. Better yet, bring in some microwaveable leftovers.