Every January for the past decade, Jessica Irish of Saline, Mich., has made the same New Year’s Resolution: to “cut out late night snacking and lose 30 pounds.” Like millions of Americans, Ms. Irish, 31, usually makes it about two weeks.

But this year is different.

“I’ve already lost 18 pounds,” she said, “and maintained my diet more consistently than ever. Even more amazing — I rarely even think about snacking at night anymore.”

Ms. Irish credits a new wearable device called Pavlok for doing what years of diets, weight-loss programs, expensive gyms and her own willpower could not. Whenever she takes a bite of the foods she wants to avoid, like chocolate or Cheez-Its, she uses the Pavlok to give herself a lightning-quick electric shock. To read more from JENNIFER JOLLY, click here.