Food intake recall and biochemical and anthropometric measurements were used to determine protein, iron, and folate nutritional status of 12 patients before and four months after gastric bypass surgery. Post-surgery intake of the nutrients was significantly lower than the Recommended Dietary Allowances. Highest levels of serum folate were observed after surgery, while serum iron levels showed no significant changes. Deficit protein intake, very low creatinine-height index, and significant changes in anthropometrics all indicated the loss of body mass. Serum transferrin levels did not differ significantly, suggesting visceral proteins were intact.