The Slaton's are larger-than-life sisters who have always relied on each other and food for support. Amy, age 31, is desperate to have children, but hasn't been able to due to her weight. While Tammy, age 32, is one step away from being bedridden.

Amy and Tammy go to Atlanta to meet Dr. Procter to discuss weight loss surgery. When they arrive, Dr. Procter gives Tammy a hefty weight loss goal before he will approve her for surgery, meanwhile the dietician has more bad news for Amy.

Amy and Tammy eagerly begin their weight loss journey. Sticking to their diets is a matter of life and death but proves to be a real struggle. The pressure to reach their goals culminates in a huge fight that threatens their diets and relationship.

After a stressful first month of dieting, the sisters head back to Atlanta for their one-month check in with Dr. Procter to find out if they are on the right path to their weight goals. The results force Amy to make a difficult decision.

Amy decides to have a real wedding ceremony because if she gets approved for surgery, she's afraid she may not survive; after the wedding, the sisters head to Atlanta hoping for a life-changing final weigh-in.

Amy undergoes gastric bypass surgery to change her life, but endangers herself by not sticking to the post-op diet. Tammy seeks support from her love interest, Jerry. Two months later, the sisters reveal the changes they've made.