The Only Protein Bar Our Editors Would Buy at Costco

Costco is full of healthy, delicious snack options—fruit bars and pistachios are just a few of our favorites. And some of the best high-protein, RD-approved snacks you can buy are protein bars. Protein is an essential macronutrient that plays a major role in keeping our bodies functioning and healthy. Snacking on a protein bar is an easy way to add more protein to your diet while also keeping you satisfied between meals.

To help you find the tastiest protein bar, we decided to try all of Costco's store-brand offerings. The Kirkland Signature line had four bars available, and the Chewy Protein Bar, Peanut Butter & Semisweet Chocolate Chip was the only one our food editors and registered dietitians liked—here's why. Plus, learn which protein bars didn't make our must-buy list.

The #1 Protein Bar to Buy at Costco

Peanut butter lovers, rejoice! Kirkland Signature's Chewy Protein Bar, Peanut Butter & Semisweet Chocolate Chip is the bar for you. Our testers were impressed with the flavor of the bar, which features a combination of peanuts, peanut butter, chocolate chips, almonds and almond butter. Protein bars can often have an artificial, lingering aftertaste, often due to ingredients like sugar substitutes and/or sugar alcohols, but that wasn't the case here. Instead, the nutty, sweet flavor of the bar had several of our testers saying "Yum!"

Our testers not only thought this bar tasted great, they thought it looked appealing and had great texture too. You can clearly see the ingredients in the bar, from the mini chocolate chips to the bits of peanuts, which was appetizing. Keeping the ingredients whole also added to the bar's texture, as the crunch of the peanuts and smooth chocolate coating blended together nicely. The chewy, crunchy texture helped this bar stand out, especially compared to the others that were taste-tested, which featured a pureed mixture of ingredients that led to a one-dimensional texture.

Of course, we can't forget about the protein in a protein bar. Here's the nutrition information for a 1-bar serving:

• 190 calories
• 11 grams total fat
• 3 g saturated fat
• 0 milligrams cholesterol
• 120 mg sodium
• 16 g carbohydrates
• 6 g fiber
• 6 g total sugars (4 g added sugars)
• 10 g protein

Thanks to the satisfying combination of protein and fiber, you're looking at a snack that will help you feel full between meals, whether you're looking for a mid-morning or afternoon bite. These bars are also gluten-free, so they're perfect if you're following a gluten-free diet.

All of these factors made Costco's chewy protein bar stand out for our testers. These protein bars are available in a pack of 42 for $18.99, which breaks down to about 45 cents per bar. If you typically buy protein bars and have room for a big box of them, grab a package the next time you're shopping at Costco.

Other Protein Bars We Tried

Costco's Kirkland Signature Protein Bars had three other flavors that we tried: Chocolate Brownie, Chocolate Chip Cookie Dough and Chocolate Peanut Butter Chunk. The major issue our testers had was the flavor. These bars, unlike our favorite one, use stevia, a no-calorie sweetener. While stevia is a natural sweetener that doesn't affect blood sugar (which can be a great option for people with prediabetes or diabetes), a major downside of the ingredient is its bitter flavor. Our testers felt like it overpowered the other ingredients in the bar and left an unpleasant aftertaste. These bars also weren't visually appealing and were too chewy at times. We'd recommend skipping these protein bars and opting for our top pick protein bar or another snack from Costco—like our food editor's favorite snack or the No. 1 snack to help you reduce inflammation—instead.