Research
Energy balance
Fasting and energy restriction upregulate the NPY system (increasing mRNA and peptide content in the arcuate nucleus), while refeeding and high-fat/high-energy diets tend to downregulate or decrease NPY expression as a counter-regulatory mechanism.
Your brain's hunger signal (NPY) increases when you fast or restrict calories to drive you to eat. However, chronic overconsumption of high-fat or high-energy foods may actually suppress this specific signal over time as a counter-regulatory response.
StrongQualifiesVERY_HIGH confidence
It is dependent on energy availability, e.g. upregulation with food deprivation or restriction, and return to baseline with refeeding... Long-term exposure to high-fat or high-energy palatable diets leads to the development of adiposity and is associated with a decrease in hypothalamic NPY content or expression, consistent with the existence of a counter-regulatory mechanism to diminish energy intake and limit obesity development.
Why this rating
Consistent findings across numerous studies on fasting, refeeding, and diet composition.
Source
Neuropeptide Y in normal eating and in genetic and dietary-induced obesity
Bernard Beck · Philosophical Transactions of the Royal Society B Biological Sciences · 2006
DOI 10.1098/rstb.2006.1855
narrative_reviewCited 278×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Central administration of Neuropeptide Y (NPY) acts as a potent orexigenic signal that stimulates food intake, specifically increasing carbohydrate preference, reducing the latency to eat, and delaying satiety to augment meal size.Strong
- The orexigenic effects of Neuropeptide Y are mediated primarily through Y1 and Y5 receptors, with Y1 playing a dominant role in appetitive behavior and Y5 in consummatory behavior.Good
- Genetic obesity models with leptin signaling failure (e.g., Zucker rats, ob/ob mice) exhibit increased NPY mRNA and peptide levels, whereas other genetic obesity models (e.g., agouti, tubby mice) show decreased NPY in the arcuate nucleus but increased expression in the dorsomedial nucleus.Good
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