During radiation treatment for head and neck cancer a large percentage of patients at Mayo Clinic Rochester develop the need for tube feeding to meet nutrition and hydration needs. These patients are usually taking pain medication along with a stool softener or laxative. Currently, when these patients get a feeding tube it is our standard practice to choose a fiber-free enteral tube feeding formula as to not worsen their constipation. Currently, there are no guidelines as to which patients are good candidates for fiber containing enteral tube feeding formulas. The investigators hope this study will help determine if fiber containing enteral tube feeding formulas can be used for patients undergoing radiation for head and neck cancer without increasing rates of constipation or increasing use of stool softeners/laxatives.

Hypothesis: Participants enrolled in the study will not have increased rates of constipation on fiber-containing enteral tube feeding formula compared to historical standards on fiber-free formula.

Inclusion Criteria:

• Cancer of: 1) lip/oral cavity 2) pharynx 3) larynx 4) nasal cavity/paranasal sinus 5) salivary gland 6) Thyroid according to AJCC cancer staging manual 6th edition 2002
• Current radiation therapy or starting radiation therapy in the next 2 weeks
• Patient must have a gastrostomy tube

Exclusion Criteria:

• Jejunostomy tube
• Diagnosis of Irritable Bowel Syndrome (abdominal pain and diarrhea or constipation lasting at least three months in one year)
• Short bowel (A patient is generally considered to have short bowel syndrome when less than 100 to 150 centimeters of functioning small bowel remains)
• Body max index (BMI) <18.5kg/m2
• Gastroparesis (when the stomach retains food for longer than normal periods). This must be diagnosed with a gastric emptying study.
• Use of Metoclopramide
• Receiving 5-FU chemotherapy

These participants have head and neck cancer, are undergoing radiaiton therapy and will have a percutaneous endoscopic gastrostomy (PEG) placed.