Reporter: They say no pain, no gain. But this is turning that phrase on its tongue? Two overweight women who can't control their eating, going to extremes to lose weight fast. A stiff plastic patch... See More
Reporter: They say no pain, no gain. But this is turning that phrase on its tongue? Two overweight women who can't control their eating, going to extremes to lose weight fast. A stiff plastic patch stitched right to their tongues will inflict a sharp pain if they try to eat any solid food. How do you feel? I feel good. My tongue is still swollen so i can't talk. It doesn't fit me anymore. Reporter: Lysander lanuza and marlene beltran each hope to drop 20 pounds in 30 days, after you get this tongue patch, you'll be able to wear these shorts? Yeah. Reporter: Tracking the difficult diet in video diaries along the way. For lysander, day one brings an immediate challenge. This is what my mom cooked for breakfast, which I obviously can't eat. Reporter: Instead -- I'm actually doing my workout right now. Reporter: She cheerfully begins the requisite 45-minute daily exercise routine. But lysander's social life is all about food, and day one brings another temptation. This is my first dinner out with my friends. Reporter: She sips iced tea while her friends gorge on a buffet. Yummy! Today is father's day and this is what we have to serve at the table. Barbecue. Fish. I cannot eat any of that. This is all I can eat, diet pepsi. Reporter: So far so good. I've lost three pounds. Reporter: But across town, marlene has a craving for just about everything. It's crazy because I don't like beans. Never liked them, won't eat them. But today, just looking at my mom eat beans made my mouth water. Reporter: By day five, this food junkie has a bad need for a fix. Lately I've been craving an in-n-out burger, like, really bad. And I want a burger really bad. A cheeseburger. Cheeseburger. I don't care if it's a bite. I just want a burger. Reporter: Somehow, marlene resists her cravings. Lysander -- not so much. I tried, like, a piece of popcorn. We were at the movie theater. And it hurt. So, I'm like, forget it. Reporter: The popcorn hurt? Yeah. Reporter: And are you thinking, yes, it's working, i don't want to eat. No, I'm like, , it does work. I can't eat. Reporter: Dr. Nikolas chugay claims the miracle of the tongue patch is that it can act as a jump-start to lasting weight loss. It's really a life-changing type of a pattern. And it takes about 30 days to change a habit. Reporter: A small patch that can be life-changing. Life-changing. Exactly. If I could say one thing, it's that the whole concept that you jump-start is absurd. Reporter: Weight-loss expert dr. Rob huizenga points to studies that show how most extreme dieters who lose weight rapidly eventually gain it all back -- and more. There's not one scintilla of hope or evidence that putting a patch on your tongue and -- and not being able to eat for a month is going to have any years or three years. Reporter: Dr. Chugay's son and partner, dr. Paul chugay, did submit a study that claims 70% of their patients lost an average of 16 pounds and kept it off for eight months. But the american academy of cosmetic surgery won't publish it without more data. No matter. Marlene is getting all the data she needs from her bathroom's scale, as the pounds fall away. My double chin is not as bad as it used to be. My arms are a lot thinner. Reporter: Lysander is also watching pounds melt away. So far I've lost 15, 16 pounds. I'm getting a lot of attention from guys. Which is nice. It's attention I'm not used to, so I'm still kind of adjusting to it. That doesn't hurt, does it? Reporter: Finally, liberation day. How does that feel? Liberating. Liberating, yes. Now, that wasn't so bad, huh? Didn't even feel it. Reporter: The final tally? Marlene loses 18 pounds. Remember those skinny jeans she couldn't wear before? Now they're kind of big on me. Reporter: Lysander loses 23 pounds. And that bikini she wouldn't dare try on before? Aloha, lysander! Once they take the patch off, we put them on the boot camp diet. It's a strict diet for another month. And then I prepare them for the regular maintenance diet that they'll stay on for the rest of their lives. Reporter: Or not. As hard as it was to live with the tongue patch, it will be harder to keep the weight off without it. I was sad the patch was coming off, just because I felt the hard part began. Like, now I'm on my own. I really don't want to go through that again. It was really hard for me. I agree to the fact that it is really an extreme measure of losing weight. Reporter: You do think it's extreme? Yes, I do. Reporter: Is it crazy? Yes, I think it is. I mean, comparable to the other diets that I know, yes it is. Reporter: Clearly, lysander, who paid $2,000 for her tongue patch, is not nearly as happy as the person who got it for free -- marlene. It wasn't bad. Reporter: Look at you. You're smiling. Like, I would do it again. Like, it was fun. The tongue patch is, like, kind of addicting. You lose the weight and you see the results fast so you want more. So, if you needed to lose the weight, would you undergo something as extreme and painful as the tongue patch? Let us know on twitter, using #abc2020. Next, fired for being too
This transcript has been automatically generated and may not be 100% accurate.