Xanthan gum (12 g/day) was fed in muffins during either the first or second half of a 12-wk period of muffin feeding, to free-living subjects. Nine subjects were diabetic, having moderately elevated serum glucose but managing without insulin or hypoglycemic drugs, and four were nondiabetic controls. Before the study and at the end of the xanthan and xanthan-free periods, bloods were taken before and 2 h after an oral glucose load. The feeding of xanthan gum lowered fasting and postload serum glucose and reduced fasting levels of total plasma cholesterol in diabetic subjects. Xanthan gum also tended to lower fasting and postload levels of gastrin and gastric inhibitory polypeptide (GIP) and fasting levels of total and VLDL triglyceride and cholesterol in VLDL and LDL fractions. Subjects reported a sense of fullness after consuming xanthan muffins but no severe digestive symptoms.