Caloric Restriction In Sarcoma Patients Treated With Pre-Operative RT

Inclusion Criteria:

* Age \>18 years
* Biopsy proven soft tissue sarcoma located in the lower extremities
* Patient to be treated with radiation therapy for a primary lower extremity soft tissue sarcoma or recurrent tumor after surgery, followed by surgical resection
* Karnofsky Score ≥ 60%
* Body Mass Index (BMI) ≥ 20 kg/m2
* Protein levels within normal limits within 45 days of enrollment
* Normal kidney and liver function within 45 days of enrollment
* Normal blood counts within 45 days of enrollment
* Normal chemistries within 45 days of enrollment

Exclusion Criteria:

* Current pregnancy and breast feeding
* Other cancers diagnosed within the last 5 years (in situ and/or invasive)
* Diabetes mellitus
* Current metformin therapy
* Other conditions may exclude participants from the study (e.g. intractable nausea/emesis, allergic reaction to shake, patient decides not to have surgery, any medical condition that prevents patient from having surgery)