Microblog: Fasting Series – What Causes Satiety

Updated series per request! Why do some start carnivore and gain weight? Let’s take a deep dive.

🤐Hormones in our body tell us we’re full. There are multiple overlapping systems that help us to stay within a normal weight range.

1️⃣Peptide YY (PYY) is a peptide hormone that signals satiety, especially with proteins. Soon after eating, PYY is secreted into the blood by cells lining the lower small intestine and the colon. The release of PYY begins even before nutrients arrive in the lower small intestine and the colon. PYY decreases food intake by inhibiting gut motility. It acts as an “ileal brake” to cause a sense of satiety.

2️⃣Cholecystokinin (CCK) is a peptide hormone that signals satiety for fat. CCK stimulates the gallbladder to contract and release stored bile into the intestine. The mechanism for hunger suppression is thought to be a decrease in the rate of gastric emptying.

3️⃣Glucagon-like peptide-1 (GLP-1) enhances satiety and reduces energy intake. It delays gastric emptying and gut motility in humans. In a study, injections of GLP-1 inhibited food intake, independent of food in the stomach or gastric emptying.

4️⃣Mechanical stretch receptors in the stomach signal to the brain that the stomach is literally stretching beyond capacity and to stop eating. Most vegetarians and heavy fiber consumers use this as their cue for satiety.

5️⃣Incretins can signal protein satiety, among other signaling. The incretin hormones are gut hormones that amplify nutrient-induced insulin secretion in response to meal intake.

6️⃣Leptin controls appetite by signaling your brain to stop eating. When leptin is properly functioning—when fat mass increases, so do leptin levels and appetite is suppressed until weight loss occurs. Leptin regulates energy intake and fat stores so that weight is in homeostasis.
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🍟Processed foods circumvent these systems and allow you to eat past satiety. This is why you can overeat sugar and processed carbs because they circumvent these signals. This holds true with vegetable oils and processed meats (e.g., sausages).⠀
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💡The big takeaway is that most of these hormones are in the gut and a part of the digestive process. To be cont’d.