An unpublished study suggests that Appethyl (an extract thylakoids in spinach from Greenleaf Medical) significantly reduces appetite, specifically for certain foods. The craving for unhealthy foods, such as sweets, was reported to be significantly reduced by Appethyl and linked to the release of the gut hormone GLP-1. The abstract of this unpublished study was presented at the winter meeting of the Society of the Study of Ingestive Behavior in Switzerland.

In the study, 36 overweight women between the ages of 40 and 65 were recruited for weight loss diet intervention for three months. Participants received a daily blueberry shot with or without 5 grams of Appethyl at breakfast. Blood glucose, insulin and GLP-1 were measured on the first and last day of the study during a period of six hours following breakfast. At various times, the urge for sweet, fat and salt as assessed using visual analogue scale (VAS). Lunch was served six hours after breakfast and subjects continued to measure their cravings for sweets, fats and salt.

The urge for sweets was significantly suppressed in those taking Appethyl after the first dosage on day one. The suppression was stronger on the last day. GLP-1 did not significantly change on day one, but the last day saw a significant increase in GLP-1 release in subjects taking thylakoids, the active components in Appethyl, compared to the control.

The study concluded that the suppression of sweet tasted may be coupled to the release of GLP-1 and this occurred through delaying food digestion as the active components in Appethyl temporarily inhibit pancreatic lipase for about two hours. This has also been shown to slow down the digestion of carbohydrates.