Peptide YY - The Body's Own Appetite Suppressant

The Stomach’s Natural Appetite-Suppressant

If you’re trying to lose some weight, a little peptide YY might help.

Peptide YY – also known as PYY – is a hormone that regulates hunger. It’s released into the blood stream in the stomach, but nothing really starts to happen until it reaches the hypothalamus; a small region of the brain that drives a wide variety of behaviors, including eating, drinking, pleasure, anger and embarrassment.

So for anyone who struggles to reduce calorie intake, it might be very beneficial to find a way to naturally trigger PYY production and sidetrack the desire to eat.

A new study reveals that a particular type of food that can do just that.

Of mice and men

When the average Western diet is compared to the estimated diet of our hunter-gatherer ancestors, two differences stand out clearly: We consume a lot more carbohydrates than they did, and much less protein. And you can be sure that widespread obesity was not a concern among people who devoted their days to hunting and gathering.

Researchers at University College London theorized that protein intake might prompt PYY production. They designed a two-phase study to evaluate PYY production in response to protein, carbohydrate, and fat intake.


  • Nine obese men and 10 normal-weight men fasted for 14 hours
  • Each subject received a meal in which most of 1,200 calories were from protein
  • After the meal, a blood sample was taken from each subject at 30-minute intervals for 90 minutes
  • Blood samples were assessed for PYY concentration
  • One week later, this procedure was repeated with a heavy carbohydrate meal, and one week later with a meal that consisted mostly of fat
  • Results showed that the protein meal prompted the highest PYY production


  • When researchers fed mice a high-protein diet, PYY levels increased, calorie intake dropped, and the mice gained less weight than mice fed a normal amount of protein
  • Mice that were genetically modified so they’d produce no PYY ate more, became obese, and didn’t respond favorably to a high-protein diet
  • When the genetically modified mice were injected with PYY, they began to lose weight

Cutting hairs

“We’ve now found that increasing the protein content of the diet augments the body’s own PYY, helping to reduce hunger and aid weight loss.”

That encouraging quote comes from Dr. Rachel Batterham, the lead researcher for the University College London team. The quote appears in a press statement, released by Cell Press, the publishers of the journal Cell Metabolism in which the study was recently published.

But the press release offers this additional, puzzling comment about Dr. Batterham’s remarks: “She also noted that such a diet would not resemble the popular Atkins diet, which is typically high in both saturated fat and protein.”

Uh how’s that again?

The Atkins diet is a high protein diet. Period. On the Atkins diet you can easily get plenty of protein while avoiding saturated fats, if you feel you must.

For instance, poultry with the skin removed is low in saturated fat, as are most fish, nuts, legumes, and lean cuts of beef (top sirloin) and pork (tenderloin). And although eggs do contain some saturated fat, they’re an excellent source of protein because they’re loaded with a wide variety of nutrients, including vitamin D, magnesium, calcium and folate.

I’m not going to get into the saturated fat issue today. But if you’d like to read some surprising facts (and myths) about saturated fats, check the e-Alert “Pure Lard” (8/22/05), which you can find at this link:

“Critical Role for Peptide YY in Protein-Mediated Satiation and Body-Weight Regulation” Cell Metabolism, Vol. 4, No. 3, September 2006,
“Eating Protein Boosts Hormone that Staves off Hunger” EurekAlert, 9/5/06,