 -- intro: When I talk to my clients about their favorite meals, many will say, “Well, I love a good sandwich.”

I get it. There’s just something very satisfying about picking up your lunch with both hands and biting in. But from a nutritionist’s point of view, a sandwich can either be a well rounded combo of nutrient-rich ingredients, or a downright dietary disaster.

Here are nine of the best and worst fillings to consider, along with a few tips to prevent sandwich calorie overkill.

quicklist: 1 category: Best and Worst Sandwich Ingredients title: Best: Avocado url: text: In addition to heart-healthy fats, which have been shown to slash “bad” LDL cholesterol and up “good” HDL levels, avocados provide anti-aging, disease fighting antioxidants and nearly 20 different vitamins and minerals, which is likely why one recent study found that avocado eaters have higher intakes of fiber, vitamins E and K, magnesium and potassium. And here’s the surprising part—regular avocado eaters weigh less and have smaller waists, even without eating fewer calories. Bonus: adding avocado to a sandwich with veggies will boost the absorption of antioxidants by up to 13 times.

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quicklist: 2 category: Best and Worst Sandwich Ingredients title: Best: Hummus url: text: Using two tablespoons of hummus rather than one of mayo as your sandwich spread provides the same number of calories for double the portion, along with bonus nutrients, including plant-based protein, vitamins, minerals, and antioxidants. To add even more flavor and color to your meal, reach for hummus prepped with veggie add-ins like roasted red peppers, or sundried tomatoes.

quicklist: 3 category: Best and Worst Sandwich Ingredients title: Best: Basil url: text: In addition to being aromatic and delicious, fresh basil has potent anti-inflammatory effects, a boon for health since inflammation is a known trigger of premature aging and chronic diseases, including obesity. It’s also rich in immune-supporting vitamin A, and its natural anti-bacterial properties have been shown to fight Staphylococcus aureus and E. coli.

14 Foods That Fight Inflammation

quicklist: 4 category: Best and Worst Sandwich Ingredients title: Best: Onions url: text: In addition to fighting inflammation, onions help fight heart disease by protecting blood vessels and reducing cholesterol. Natural compounds in onions have also been shown to boost bone density, bolster immune defenses, balance blood sugar, and ward off chronic diseases, including cancer. Fresh red and sautéed yellow onions are my favorite sandwich additions, but choose any type you like to reap the benefits.

quicklist: 5 category: Best and Worst Sandwich Ingredients title: Best: Vinegar url: text: This lip-puckering condiment is low in calories (usually no more than 15 per tablespoon), packs antioxidants, and its main component, acetic acid, has been shown in research to help control blood pressure and blood-sugar levels while curbing fat accumulation. Sprinkling it on a sandwich may also be a savvy weight-control strategy. One study, published in the Journal of the American College of Nutrition, found that adding vinegar to meals can help naturally curb calorie intake for the remainder of the day. The effect shaved off 200 to 275 calories, the amount burned in a 30-minute elliptical session. Go for balsamic, red wine, champagne—any type you like to add a nutritious layer of flavor.

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quicklist: 6 category: Best and Worst Sandwich Ingredients title: Worst: White bread url: text: A recent Spanish study that tracked the eating habits and weights of more than 9,000 people found that those who ate only white bread and downed two or more portions a day were 40% more likely to become overweight or obese over a five-year period, compared to those who ate less than one portion of white bread a week. This study backs other research to support the notion that if you eat bread, consuming a 100% whole-grain version is the best choice for curbing obesity risk, and fending off a number of chronic diseases, including type 2 diabetes, heart disease, stroke, and certain cancers. Make the switch, or opt for a breadless sandwich instead (see below).

quicklist: 7 category: Best and Worst Sandwich Ingredients title: Worst: Processed meat url: text: Processed meats like pastrami, salami, and pepperoni, are meats that aren’t simply cuts of an animal’s muscle (such as chicken breast), but rather meats processed with additives and preservatives. These items are generally higher in calories, fat, and sodium—for example, 3 ounces of fresh cooked chicken breast contains about 90 calories, 1 gram of fat, 50 mg of sodium, and 20 grams of protein. One ounce of pepperoni, on the other hand, has 130 calories, 11 grams of fat, 480 mg of sodium, and 6 grams of protein. In addition, in a large scale study which involved 10 countries and almost half a million men and women, European researchers concluded that there is a solid link between the consumption of processed meats and heart disease as well as cancer. In addition, the risk of death from all causes rose along with the intake of processed meats.

quicklist: 8 category: Best and Worst Sandwich Ingredients title: Worst: Ranch Dressing url: text: In addition to less than stellar ingredients like sugar, artificial color, and preservatives, a two-tablespoon portion of this popular sandwich dressing packs 130 calories and nearly 400 mg of sodium (of the recommended daily cap of 1,500 to 2,300 mg). If you love the texture and tanginess, whip up a cleaner version made with nonfat organic plain yogurt, seasoned with a touch of Dijon, lemon juice, minced garlic, black pepper, and Italian herbs.

quicklist: 9 category: Best and Worst Sandwich Ingredients title: Worst: Imitation cheese url: text: Perhaps the name gives it away, but imitation cheese is on my “yikes!” list. A quick scan of the ingredient list will likely reveal additives such as corn syrup, sugar, salt, and preservatives, and a two tablespoon portion packs about 100 calories and 500 mg of sodium (one tablespoon is about the size of your thumb, from where it bends to the tip). If you really need some cheese, keep it all natural, or opt for a creamy plant-based alternative instead like guacamole.

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quicklist: 10 category: Best and Worst Sandwich Ingredients title: Extra tips for preventing sandwich calorie overkill url: text: Go open-faced: a smart way to immediately slash carbs in half without giving up the heartiness of bread.

Opt for veggies instead: if you’re not a huge bread fan, wrap your sandwich fillings in outer Romaine leaves instead (so great if you have a “crunch” tooth!).

Swap your starchy sides: if you do include bread, trade more carb-laden accompaniments (like chips, pretzels, crackers) for a side salad, or something like chopped or shredded veggies dressed in balsamic vinaigrette.

Cynthia Sass, MPH, RD, is 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 Rangers NHL team and the Tampa Bay Rays MLB team, and is board certified as a specialist in sports dietetics.

This article originally appeared on Health.com.