We usually think of blood glucose as representing the body’s cathohydrate metabolism and it is a useful index (1). The concentration at any point reflects the balance between entry of glucose into blood from the gut or from gluconeogenesis, principally in the liver, and removal by peripheral tissues for energy metabolism, storage as glycogen, or conversion to fat or, with hyperglycemia, removal via glycosuria. Conceivably, any of these events might be affected directly or indirectly by dietary fiber (Fig 1). Ofthem, only some of those in the gut are definite but current work on dietary fiber physiology is making others more likely. Some regulators of blood glucose, hormonal, and other energy substrates, may be affected by dietary fiber. For example, insulin secretion may be modulated by gut hormones where release is in turn influenced by dietary fiber (2, 3). Volatile fatty acids (VFA) are products of dietary fiber metabolism by colonic microflora and reach significant concentrations in the splanchnic circulation (4-7). If energy balance is altered by dietary fiber, free fatty acid (FFA) flux may in turn be altered. These are questions deserving further investigation. More so since variables like serum insulin and plasma free fatty acids have predictive power for health outcomes in their own right (8).