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In this third and final installment of the series, “Appetite Hormones 101”, we will discuss Peptide YY (PYY). The purpose of this series is to explain the role of hormones on both appetite and body weight goals, as it relates to both weight loss and weight restoration. If you’re a new reader, be sure to check out “Appetite Hormones 101: Leptin” and “Appetite Hormones 101: Ghrelin“.
Peptide YY (PYY)
PYY is a hormone that suppresses appetite. It was discovered to play a role in digestion in 1985. PYY regulates food intake, and is believed to improve leptin sensitivity. The amount of PYY released by our bodies is influenced by the number of calories we ingest; the more calories we ingest, the more PYY is released. The diagram below shows how our PYY levels, ghrelin and leptin levels typically fluctuate before and after meals:
PYY levels are highest in individuals battling anorexia, followed by those individuals that are lean,which explains why both groups have less hunger and also may have more difficulty eating. PYY levels are lowest among obese and morbidly obese individuals. Individuals with bulimia also experience low levels of PYY, which helps to explain why all three groups feel more hunger. Research shows that the obese individual can decrease their PYY levels by 30% by reducing their body weight by 5.4%. PYY levels are not believed to be effected by weight restoration during recovery from anorexia. It is also important to note that high levels of PYY in anorexic individuals is associated with decreased bone mineral density (BMD).
Our mood also effects our PYY levels. Recent studies show that PYY levels are higher in those suffering from major depression. This explains why many people with major depression have a decreased appetite and experience weight loss.
PYY levels can be regulated through both diet and exercise. Diets high in quality protein tend to raise PYY levels highest, followed by diets high in healthy fats. High carbohydrate diets tend to raise PYY levels the least. Aerobic exercise has also been proven to raise PYY levels, whereas strength-training has no effect on PYY levels (although strength-training does lower ghrelin levels).
In conclusion, PYY regulates our appetite. The higher our PYY levels are, the more satiated we will feel. You can ensure your PYY levels are highest by eating a high protein diet and including aerobic exercise in our workout routine.
Medical Advice Disclaimer: The information included on this site is for educational purposes only. It is not intended nor implied to be a substitute for professional medical advice. The reader should always consult his or her healthcare provider to determine the appropriateness of the information for their own situation or if they have any questions regarding a medical condition or treatment plan. Reading the information on this website does not create a physician-patient relationship.
© 2012, Dr J Renae Norton. This information is intellectual property of Dr J Renae Norton. Reproduction and distribution for educational purposes is permissible.
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J Endocrinal Invest. 2011 Dec 15 [Epub ahead of print]