Transcript for Here Comes the Bride
keep it up, no slowing down. With just four weeks to go before the final weigh in, it's the home stretch before our battling brides must walk down that aisle. Kick it into gear! Bootcamp is more brutal than ever. It doesn't get easier because you're pushing yourself harder and harder every time. Even amber is feeling the pain. Bootcamp is still hard. I don't know if it will ever be easier. It's not supposed to be easy and I think that's what doug reminds me. If I'm trailing lagging along he's like amber, you can do it, finish it out. I'm like doug is watching, i need to prove myself. Bolstered by the success of her first weigh in, amber lets her sweet tooth lead her astray. I want cake and I'm going to devour it. It's going to be high in carbs and slow down your metabolism. Wish me luck. Apparently it wasn't the only time her fiance devin found proof hidden under the couch. I have been researching -- look what we found. That's not mine. I don't eat these. She likes to munch on things. Carly's grueling schedule is almost too much. Most of the time I'm going on four to five hours of sleep. I am completely worn out and i want to cry. Is this worth it? I had the most amazing man. I want to celebrate that. I want him to see me as the person that he met, this gorgeous girl. Almost there, a few more seconds on this one. So the wedding date gets closer do you have to crack the whip harder? It's the opposite. As the wedding gets closer they are more motivated and they want to come more often. I'm disappointed. I'm not seeing the result that i had hoped for. For sarah the pressure of planning her dream wedding is finally taking its toll. It's a little stressful just because it's coming down to the wire. The one thing that I struggle with is that when I get stressed out I just want to eat. But with an intense desire to look perfect on the big day as incentive -- I'm definitely more motivated after the weigh in. It's do or die now. The time is here. Now you have to get in shape. Help from her fiance along the way. Chris made me this lovely green smoothie. What's in it? Kale? You can eat kale all day. She's able to stay away from the junk. That's awful. And even finish a 5k. After eight weeks of blood, sweat and a lot of tears -- what are you looking forward to the most? Cake. Wedding gowns are fitting, the brides are blushing. This is high school skinny for me. She needs it taken in about an inch through the waist. That's awesome. I didn't know I would have to. It turns out the dress might not be the most important part anymore. It goes beyond bootcamp. It's going to make me a better wife, a better mom, a better friend. At the final weigh in their drill sergeant is brimming with pride. Give all three of them a hand. There can only be one winner. Drum roll. Sarah and carly dropped a lot of weight but with a loss of 21 ds, amber wins the title. You got a sash for your sweat. Amber is now ready to collect here prize, a sexy photo, the perfect wedding gift for the groom. But the real motivator of course was always this. This gown, this perfect moment, amber's wedding day is finally here.
This transcript has been automatically generated and may not be 100% accurate.