The Slatons 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 because of her weight; white 32-year-old-Tammy is one step away from being confined to her bed.
Amy and Tammy go to Atlanta to meet Dr. Procter to discuss weight-loss surgery; Dr. Procter gives Tammy a hefty weight-loss goal before he will approve her for surgery; the dietitian 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 their 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 to family and friends.