Chugay's son and partner, Dr. Paul Chugay, submitted to the American Journal of Cosmetic Surgery a study claiming that 70 percent of their patients lost an average of 16 pounds and kept it off for eight months.
The journal refused to publish it without more data.
On day 8, Beltran said, "My double chin is not as bad as it used to be. My arms are thinner. My stomach is not as flabby."
By day 20, Lanuza had lost 15 pounds.
On day 22, Beltran said, "I'm getting a lot of attention from guys. It's attention I'm not used to, so it's nice."
The final tally: Beltran lost 18 pounds, Lanuza 23.
"Once they take the patch off, we put them on the boot camp diet," Dr. Nikolai Chugay said. "It's a strict diet, kind of plant-based diet that patients are placed on for another month. And then, I prepare them for the regular maintenance diet that they'll stay on for the rest of their lives."
Or not. Within hours of having the tongue patch removed, Lanuza enjoyed her favorite feast: Korean barbecue.
Beltran cracked after three days, having a slice of cake and two tacos.
She said she has no regrets about getting the tongue patch.
"It was great," said Beltran -- who, remember, had the procedure done for free. "It wasn't hard for me to do it. And I found the shakes really good."
Lanuza felt differently.
"I don't want to go through that again," she said. "It was really hard for me."
"It is really an extreme way to lose weight," Lanuza added.
Is it crazy?
"Yes, I think it is," she said. "I mean, comparable to the other diets that I know, yes."
Watch the full story, including Lanuza and Beltran's video diaries, on "Nightline" TONIGHT at 12:35 a.m. ET.