When sinful treats and fast food lunches fill up your days at the office, it's hard to stick with a healthy diet. Just make sure you steer clear of these seven deadly diet sins to keep your healthy motives on track.

When you're bombarded with sinful treats from well-meaning coworkers or heading off on yet another fast food lunch for a mid-day refueling session, sticking with a healthy diet at the office may seem impossible.

Eating out regularly and snacking on sugary foods throughout the day is the fast track to weight gain, and day-to-day stresses can make it even harder to stick with a diet plan. When you're stuck behind a desk all day, one of the keys to staying fit is to steer clear of the deadliest diet sins - the fat traps at the office holding you back from getting in shape. Here are just seven deadly diet sins to avoid at the office:

1. Morning Donuts. Those Monday morning meetings can quickly turn into a diet catastrophe with the donut plate, that innocent-looking platter of sugar and fat-laden treats to accompany your coffee.

2. Birthday Treats. Coworkers' birthdays are the easiest way to fall off your diet course, but all those baked goodies can easily add up to extra pounds around the waistline.

3. Vending Machine Snackfest. When stress levels run amock, it's easy to head off to the vending machine for a quick snack. Unless you're craving granola bars or a bag of pretzels, you'll be vulnerable to potato chips, cream-filled cakes and candy bars that can do more harm than good.

4. Soda Pick-Me-Ups. Loading up on sugar and caffeine might help you get through the day, but they won't be helping your fitness aspirations. Sugary soda will also take you on a sugar high-low ride, leaving you even more vulnerable to overeating when you crash.

5. Mid-afternoon Chocolate Attacks. When a negative mood and low energy levels unite, you may be at risk for a chocolate fix. The mid-afternoon slump is the window of opportunity for the devil's food indulgences, so eat a healthy lunch to combat cravings for good.

6. Candy Jar Social Hour. When coworkers serve up candy and sugary treats at their desk, make sure to say 'thanks, but no thanks' to avoid a diet catastrophe.

7. The Office Bake-Off. While it's hard to resist your colleague's homemade chocolate brownies, 'just saying no' can help you say 'yes' to a healthier body in a few short weeks.