Eating a high-protein diet leads to higher levels of the satiety hormones GLP-1 and CCK and lower levels of the hunger hormone ghrelin after meals, which results in decreased appetite and reduced...
Mechanism
Synthesis from 1 study
Eating more protein makes the gut release signals that tell the brain you're full and stops the stomach from sending hunger signals. This makes you eat less without trying. Other effects like burning more calories or keeping muscle mass help with weight loss too, but they don't directly reduce...
Most probable mechanism
When a person eats a high-protein meal, the protein breaks down in the small intestine and triggers cells there to release hormones that signal fullness to the brain. These hormones slow down the stomach and send messages through nerves to the brain, making the person feel less hungry. At the same time, the stomach stops releasing the hunger hormone. With less hunger and more fullness signals, the person eats fewer calories without trying.
Dietary protein is digested in the small intestine and stimulates enteroendocrine L cells to release GLP-1 and enteroendocrine I cells to release CCK
GLP-1 and CCK bind to receptors on vagal afferent nerves and hypothalamic nuclei, transmitting satiety signals to the central nervous system
High-protein intake suppresses ghrelin secretion from gastric P/D1 cells, reducing circulating acylated ghrelin levels
Reduced ghrelin and increased GLP-1/CCK signaling decrease appetite and reduce daily caloric intake
Less supported by current evidence, but not ruled out
Eating protein requires more energy to digest and process than eating fats or carbohydrates. The body burns more calories turning protein into usable components and building new proteins, which raises overall energy use and reduces the surplus available for fat storage.
Dietary protein is broken down into amino acids in the gastrointestinal tract and absorbed into the portal circulation
Amino acids are transported to the liver and other tissues for deamination, urea synthesis, and protein synthesis, processes requiring ATP and generating heat
Increased metabolic activity during protein turnover elevates resting energy expenditure
When calories are restricted, eating more protein provides amino acids that activate a cellular pathway in muscle cells to prevent muscle breakdown. Preserving muscle mass maintains metabolic rate and prevents the body from slowing down energy use during weight loss.
Dietary protein delivers essential amino acids, especially leucine, to skeletal muscle
Leucine binds to and activates the mammalian target of rapamycin (mTOR) complex 1 in muscle cells
mTOR activation increases translation initiation and ribosomal biogenesis, enhancing muscle protein synthesis and suppressing ubiquitin-proteasome-mediated proteolysis
Eating more protein reduces the liver's production of fat-carrying particles called VLDL. This lowers fat levels in the blood and reduces fat storage in tissues, improving metabolic efficiency and reducing energy surplus.
High-protein intake alters hepatic lipid metabolism, reducing de novo lipogenesis and fatty acid esterification into triglycerides
Reduced VLDL secretion decreases circulating triglycerides and LDL-C precursors
Improved lipid profile enhances peripheral lipid uptake and reduces ectopic fat deposition
Evidence from Studies
Supporting (1)
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Contradicting (0)
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Gold Standard Evidence Needed
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