Research
Hormonal
Neuropeptide Y (NPY) and Agouti-Related Protein (AGRP) are potent orexigenic peptides that increase food intake and decrease energy expenditure, particularly when leptin signaling is low.
When you are in a caloric deficit, your body increases NPY and AGRP to make you hungry and slow your metabolism. This is a normal survival mechanism.
GoodSupportsHIGH confidence
When energy stores are low, production of leptin from adipose tissue, and thus circulating leptin concentrations fall, leading to increased production of hypothalamic neurotransmitters that strongly increase food intake, such as neuropeptide Y (NPY), galanin and agouti-related protein (AGRP)...
Why this rating
Supported by knockout mouse studies and human genetic data.
Source
Neuropeptides and appetite control
John Wilding · Diabetic Medicine · 2002
DOI 10.1046/j.1464-5491.2002.00790.x
narrative_reviewCited 188×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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- Alpha-melanocyte-stimulating hormone (α-MSH) and Cocaine- and Amphetamine-Regulated Transcript (CART) reduce food intake and increase energy expenditure, acting as counter-regulatory peptides to NPY and AGRP.Good
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