SAN FRANCISCO — Siren Snacks, a brand of plant protein bites, is adding a collection of keto-friendly options featuring a creamy nut butter filling.

The snacks are sweetened with monk fruit and formulated with almonds, cashews or peanuts, sustainably sourced palm oil, and chicory root fiber. Varieties include chocolate peanut butter, coconut caramel and maple almond butter.

Siren Snacks’ keto-friendly products join a lineup of protein bites containing pea protein, nuts and dates, which are available in more than 6,000 retail outlets, including Target, Kroger and CVS. Packaged in single-serve, resealable pouches, the flavors range from indulgent to functional, including chocolate chip cookie dough, birthday cake and lemon poppyseed, as well as chai tea latte, matcha latte and mocha chip.

Sisters Elizabeth and Abby Giannuzzi developed the initial recipes several years ago after struggling to find snacks in the marketplace that delivered the taste, nutrition and quality they desired. The newest additions were inspired by consumer requests for reduced-sugar options and were in development for about a year, said Elizabeth Giannuzzi, chief executive officer.

“We’re always asking our customers, ‘What do you want to see from Siren next? What are you excited about in terms of ingredients, flavors and nutrition profiles?’” she said. “Over the last two years we heard a lot that people wanted low-sugar and keto-friendly. We also got requests a lot for peanut butter and different nut butter flavors.”

She noted that many options in the market include dairy or artificial ingredients. Like all other Siren Snacks products, the brand’s new keto-friendly bites are vegan and contain no gluten, grains, soy, artificial flavors or artificial sweeteners. The products are USDA certified organic and Non-GMO Project verified.

“As a company that focuses on making plant-based clean label products we felt there was a lot of room to differentiate ourselves from competitors in the low-sugar, ket0-friendly snacking space,” she said.

Each serving contains 200 to 210 calories, 2 to 3 grams of sugar and 4 to 6 grams of net carbohydrates.

Siren Snacks’ new keto-friendly bites are launching at Whole Foods Market stores in Northern California. The chocolate peanut butter variety will roll out to Target stores nationwide this spring. The products also are available online at sirensnacks.com.