_____ is a protein secreted by fat cells and, when abundant, causes the brain to increase metabolism and decrease hunger.
There are no foods that contain leptin because it cannot be taken orally. Leptin is a hormone or protein that is produced in the fat cells of the body. It has different roles in the body, including telling the brain there is enough energy stored in the fat cells, which triggers the feeling that a person needs to stop eating. 1 It normally indicates hunger: “If your stomach’s growlin’, you’re making ghrelin.” Though, it can also be released after a high-protein meal.  Neuropeptide Y (NPY) is an extremely potent stimulator of feeding behavior. It is also the most abundant neuropeptide in the brain. Here is a quick overview of this complex and fascinating network. Ghrelin, the most predominant “hunger hormone” identified to date, is a peptide released by endocrine cells mostly within the stomach’s lining. It counteracts leptin to increase metabolic efficiency and stimulate appetite. Leptin and ghrelin seem to be the big players in regulating appetite, which consequently influences body weight/fat. When we get hungrier, we tend to eat more. When we eat more, obviously, we maintain our body weight or gain that weight back. Both leptin and ghrelin are peripheral signals with central effects. In other words, they’re secreted in other parts of the body (peripheral) but affect our brain (central). Leptin is secreted primarily in fat cells, as well as the stomach, heart, placenta, and skeletal muscle. Leptin decreases hunger. Ghrelin is secreted primarily in the lining of the stomach. There are different terms that were used to refer to leptin, including fat hormone, obesity hormone and starvation hormone. Many scientists prefer to refer to it as the starvation hormone because high levels of leptin causes a person have cravings and hunger. Leptin was discovered in the human body in 1994. Therefore, there is no leptin in food even though the term leptin-rich foods is a popular term. From the WebMD Archives. It's been called the obesity hormone or fat hormone -- but also the starvation hormone.. When scientists discovered leptin in 1994, excitement arose about its potential as a blockbuster weight loss treatment. Even today, the Internet is loaded with sites that sell leptin supplements. Leptin is a protein that's made in the fat cells, circulates in the bloodstream, and goes to the brain. Leptin is the way your fat cells tell your brain that your energy thermostat is set right, Lustig says. Ghrelin was discovered 7 years after leptin, but after the leptin letdown, there was much less fanfare. Leptin is a hormone that is a result of a buildup of fat, so it’s a long term regulator of body weight. 1 Peptide YY (PYY) has been shown to slow digestion, suppress appetite, and significantly reduce food consumption.  Cholecystokinin (CCK) is released in the duodenum in response to high-fat or high-protein meals. It signals the brain to produce a sense of fullness or satiety. Fatty meals are an especially effective trigger in the release of CCK. In leptin resistance, your leptin is high, which means you're fat, but your brain can't see it. In other words, your brain is starved, while your body is obese. And that's what obesity is: it's brain starvation.. Not only is leptin part of the hunger system, it's also part of the reward system, Lustig says.
Leptin