Whether your weakness is nonstop grazing or a "treat yourself" tendency, here's how to clean up your office diet.

Your occasional splurge becomes a regular thing

The makeover: It happens all the time: An afternoon treat to break up a stressful workday—like a mocha topped with whipped cream or peanut butter pretzels—progresses from a once-in-a-while indulgence to a daily habit. If you've developed "treat creep," as I call it, swap your goodie for a healthy substitute for 30 days, then reintroduce it in a scheduled way (for example, have it on the first Friday of each month). The splurge will become special again, and you'll likely slash hundreds of calories a week.

You nibble all day

The makeover: You might graze because you've heard it's good to eat small, frequent meals, but you could be overloading on calories. A University of Illinois at Chicago study found that women who snacked midmorning (between 10:30 and 11:30) lost significantly less weight than those who didn't. Also, a higher proportion of midmorning snackers ate more than one snack a day, which can impede weight loss. Snack only when you're hungry and to prevent going too long between meals. For most of us, that's one snack a day, between lunch and dinner.

RELATED: 10 Healthy Veggie Snack Recipes Packed With Flavor

You never bring a snack and end up scavenging

The makeover: When you're hunting down office grub, chances are you'll stumble upon Cheetos rather than fruit. So get into the habit of packing a smart snack. Assemble it when you do something that's already part of your daily routine, like cleaning up after dinner. Prep time can literally be one minute.

You lose all willpower when faced with office celebrations

The makeover: Create room for extras by reining it in elsewhere. Planning on having a cupcake? Order a chopped salad at lunch to prevent carb overload. It's also perfectly OK to wish your office mate happy birthday without downing cake if it's just not worth the trade-off (e.g., more time on the elliptical).

3 surprising vending machine picks

If feeding a machine a buck or two and pressing a button is your only choice (we've all been there!), make the best of it with these preferred options.

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Nuts or sunflower seeds

They're whole foods full of plant-based protein and usually have less sodium than processed snacks.

Popcorn

It's a whole grain and provides fiber. A single-serve bag typically packs only 11 grams of carbs, compared with about 23 grams in a single-serve bag of pretzels.

Plain potato chips

The classic kind commonly contain just potatoes, oil and salt, while you'll find a laundry list of iffy ingredients in cheesy puffs and flavored chips.

RELATED: 17 High-Protein Snacks You Can Eat On the Go

Cynthia Sass is a nutritionist and registered dietitian with master’s degrees in both nutrition science and public health. Frequently seen on national TV, she’s Health’s contributing nutrition editor, and privately counsels clients in New York, Los Angeles, and long distance. Cynthia is currently the sports nutrition consultant to the New York Yankees, previously consulted for three other professional sports teams, and is board certified as a specialist in sports dietetics. Cynthia is a three-time New York Times best-selling author, and her brand new book is Slim Down Now: Shed Pounds and Inches with Real Food, Real Fast. Connect with her on FacebookTwitter and Pinterest.