Posted on: Saturday, October 2, 2004
PRESCRIPTIONS
Hormones play role in gaining, losing weight
By Amy Tousman
Q. How can hormones produced by our bodies influence our weight?
A. Our appetites and the amount of fat our bodies store are influenced by the interaction between hormones produced by our bodies and brain chemicals. Some hormones involved in these processes are ghrelin, cholecystokinin, PYY, insulin, and leptin.
Ghrelin, produced by the stomach, lets the brain know when your stomach is empty and you are hungry. Cholecystokinin, produced by the intestines, signals the brain that we are full. Eating slowly allows the fullness message to reach the brain before you overeat.
PYY helps curb your appetite between meals. High-fiber foods increase blood levels of PYY. This may be one way these foods help control our weight.
Insulin influences how much sugar is burned for energy and how much is stored as fat.
Leptin, produced in the fat cells, works to keep body fat levels steady. When leptin levels are high, the brain decreases the appetite. When you try to lose weight, your fat stores decrease and leptin levels fall. The brain assumes you are starving and increases your appetite so that you can replenish your fat stores.
The body's ability to store fat during times of scarcity is a survival mechanism left over from prehistoric times. When food was scarce, the body would slow itself down so that fewer calories were burned and more were conserved. This still happens to us today if we try to lose weight too quickly or regularly skip meals.
Research suggests that some obese people are not getting the chemical signals to their brains that tell them to stop eating. In addition, overconsumption of fatty and fried foods, sugars, and white starches on regular basis can disrupt these signals.
They do this by increasing the levels of fats in the blood. This may interfere with leptin and insulin's actions on the brain, leading to an erroneous signal that the body is in danger of starving.
Hormonal variations can influence our appetites, metabolisms and weight. Even so, we can choose to be physically active rather than couch potatoes. We can choose healthy meals rather than super-sized portions of high-calorie foods.
We can pay attention to our body's hunger and fullness signals. This means we should stop eating when our physical hunger is satisfied. We should not be eating just because we are bored, stressed, or upset.
Amy Tousman is a registered dietitian with the Health Education Center of Straub Clinic & Hospital. Hawai'i experts in traditional medicine, naturopathic medicine and diet take turns writing the Prescriptions column. Send questions to: Prescriptions, Island Life, The Honolulu Advertiser, P.O. Box 3110, Honolulu, HI 96802; islandlife@honoluluadvertiser.com; or fax 535-8170. This column is not intended to provide medical advice.
