Appetite is controlled by the brainstem and hypothalamus area of your brain in response to peripheral signals from the stomach, according to research by Katherine Simpson, published in "Endocrinology and Metabolism Clinics of North America" in 2010. Gut hormones are released after your meal and signal feelings of satiety to your brain. Yet, the brain is able to overcome the feelings of satiety when palatable food is available. Nonetheless, certain foods and components of food may suppress your appetite.
For many years, scientists thought that complex carbohydrates had the greatest effect on suppressing appetite. However, new research reveals that protein consumption has an even greater effect. Research by Ahmed Bensaid, published in "Physiology and Behavior" in 2002, demonstrates that protein has a greater satiating effect in rats than carbohydrates. Moreover, the research shows that the larger the portion of protein, the larger the satiating effect, regardless of protein quality. Research by Margriet Veldhorst, published in "British Journal of Nutrition" in 2010, found that appetite suppression in adults is greater on a high-protein diet without carbohydrates than a high-protein diet with carbohydrates exchanged for fat.
Food Odor From Dark Chocolate
Food-related odors modify hunger and satiety regarding ingestion of a particular food, according to research by Martin Yeomans published in "Physiology and Behavior" in 2006. Some food odors may increase appetite, induce salivation and release stomach acid and insulin -- a hormone that responds to and transports blood sugar into muscle. Other food odors may suppress appetite. Eating and especially smelling dark chocolate suppresses appetite. Research by Elske Massolt, published in "Regulatory Peptides" in 2010, discovered that both smelling and eating dark chocolate suppress appetite, yet smelling dark chocolate results in satiation that is correlated with low levels of ghrelin -- a hormone that stimulates hunger. The research concludes that smelling dark chocolate may have a greater effect on suppressing appetite than eating chocolate.
Cancer and Cancer Drugs
Some medical conditions and drugs have side effects that may decrease your appetite. Cancers of the colon, ovaries, stomach and pancreas may cause your appetite to decrease, according to MedlinePlus. Zometa is a prescription drug that contains zoledronic acid and is indicated for treatment of cancers of the bone and prostate. Zometa is administered by intravenous infusion. According to the product label, 13 percent of subjects receiving intravenous infusion of Zometa experienced decreased appetite.
Depression and Antidepressants
Depression is characterized by sadness, feelings of worthlessness and loss of interest in pleasurable activities. Appetite disturbance is a symptom of depression, according to research by Melissa Maxwell and published in "Clinical Psychology Review" in 2009. Lexapro is a prescription drug that contains escitalopram oxalate and is indicated for treatment of major depressive disorder. Decreased appetite has been reported by 3 percent of subjects taking Lexapro in clinical trials.