The basic criteria for surgery is issued by NIH, and the insurance companies will go by this.
1.
BMI (body mass index) of 40 or more--about 100lb overweight for men,
80lb overweight for women.
2.
BMI 35-39.9 with serious obesity related health problems, such as type 2 diabetes, heart disease, or severe sleep apnea.
3. An understanding of the operation and the life style changes one will need to make.
If you are looking into surgery, this is your starting point of whether you qualify.
Suggested reading:
Gastrointestinal Surgery for Severe Obesity