As easy as it is to say you'll skip lunch and just eat whatever you can find around the office, you know in your heart that's not a healthy thing to do. And while that's totally fine every once in awhile, it's easy to make a habit of it. For future reference, here are some things you should try and avoid packing and/or eating for lunch, whether it be because it won't fill you up or because it's straight-up not good for you.
Pasta With Meat Sauce

Here you have a lot of carbs and a lot of heavy meatiness. Does that sound like something that's going to keep you alert throughout the day? Save all that meaty pasta goodness for later in the day when you have nothing else to do but go to sleep.
Pasta (In General)

All those refined carbs we just mentioned? Those alone—or with just any other sauce that's not meat-based—are not going to keep you full and are just not good for you. Whole grain or vegetable pastas are a whole other story, though.
Pre-Packaged Sandwiches

Anything that can be bought in a convenience store or vending machine tends to be loaded with preservatives that I know you know are not good for you.
Vegetable Soup

On its own, veggie-based soups are fantastic. They're packed with nutrients, are low-cal, and have tons of good fiber. That said, they have little-to-no protein, meaning you'll be hungry again about 10 minutes after finishing your lunch. You know what happens then—snacks every 10 minutes until you can leave the workplace. Make sure you add something hearty into the mix, like lentils or chickpeas.
PB & J

While it's certainly not the worst thing on this list, it's not the best either. Jelly's packed with sugar and white bread isn't great, either. Peanut butter is great, though. Put that on some whole wheat or sourdough and load it up with low-sugar fruits. Good job, you!
Juices

Sugar! Sugar! So much sugar! Also, no protein! None!
Iceberg Lettuce-Based Salads

Iceberg lettuce isn't bad for you, of course, but it's also generally topped with the highest-fat dressings this world has to offer. If you're going to curb what you're putting on top of it to things other than cheese, bacon, and ranch, by all means, go ahead! (But also, go ahead regardless. Eat whatever you want.)
Mac & Cheese

Assuming this is an issue of convenience again, you're likely bringing in leftover boxed stuff. Goodness knows it tastes great, but it'll lead to yet another mid-afternoon crash...and snack attacks for days.
Burgers And Fries

Drive-thru burger combos in particular are super high in calories and fats—and not the good kind.
Leftovers

Regardless of the cuisine, your second- or third-day take-in dish likely has all sorts of sugars and added ingredients you wouldn't have normally put in your own food. Just something to consider when heating up that Kung Pao chicken. Again.
Birthday Cake

We've all done it—truly, all of us—but repeat after me: "skipping lunch to just eat cake that's been sitting in your office is not a good idea." It's not saving you calories, providing you with anything healthy, nor will it fill you up so that you're snacking less later. The trifecta!