In most people without an underlying disease process, blood sugar spikes are temporary. The body works hard to regulate blood sugar and maintain it within parameters compatible with health. As a result, if behavior or circumstances--such as the consumption of a high-sugar or high-starch meal that's low in fiber, fat or protein--produce high blood sugar, the high levels will be temporary. Nevertheless, there are a number of physiological effects of temporary high blood sugar in the body.
Insulin Release
The first effect upon the body when blood sugar levels rise is that the pancreas responds by releasing the hormone insulin. Drs. Mary Campbell and Shawn Farrell, in their book "Biochemistry," explain that insulin is a peptide, or protein-based hormone. This makes it fast-acting, as compared to steroid hormones such as testosterone and estrogen. Insulin has effects within moments of release into the bloodstream. After the pancreas releases insulin, the hormone binds to receptors on body cells and causes them to take up blood sugar. This works to reduce blood sugar levels to within normal ranges.
Glycogen Formation
Another important effect of high blood sugar is that it leads to glycogen formation. Blood sugar is a common name for the biomolecule more scientifically known as glucose, which is a simple sugar. The body stores extra glucose for use during periods of fasting, in the form of a long chain of glucose molecules called glycogen. Both the liver and muscles store glycogen, note Drs. Reginald Garrett and Charles Grisham in their text, "Biochemistry." High blood sugar levels turn on an enzyme, called glycogen synthase, that combines glucose units into glycogen. In this way, excess glucose becomes available for later use and is removed from the bloodstream.
Fat Storage
The body can only store a certain amount of glycogen because it's relatively bulky. Fat, on the other hand, is nutritionally dense and takes up relatively little space for its caloric content. So temporarily high levels of blood sugar serve as a signal to the body to convert some of the excess glucose into fat. Enzymes involved in normal sugar metabolism break glucose into a much smaller molecule, called acetyl-CoA, which enzymes of lipid synthesis then begin to work on in order to convert the acetyl-CoA into a very large fat molecule. In her book "Human Physiology," Dr. Lauralee Sherwood says the higher blood sugar levels get on a temporary basis, the more likely the body is to produce and store excess sugar as fat.
References
- "Biochemistry"; Mary Campbell, Ph.D. and Shawn Farrell, Ph.D.; 2005
- "Biochemistry"; Reginald Garrett, Ph.D. and Charles Grisham, Ph.D.; 2007
- "Human Physiology"; Lauralee Sherwood, Ph.D.; 2004
