Adaptation of lipid-induced satiation is not dependent on caloric density in rats.
Food intake is modulated by ingestive (gastrointestinal) and post-ingestive signals; ingested fat is potent to produce short-term satiety (satiation) but this can be modified by long-term ingestion of a high fat diet.


OBJECTIVE
Determine whether altered lipid-induced satiation is dependent on the fat content of the diet, rather than increased caloric density or changes in adiposity.


METHODS
Initial experiments determined the differences in the microstructure of meal patterns in rats fed a high fat diet (HF: 38% fat kcal) and in rats pair-fed an isocaloric, isonitrogenous low fat diet (LF: 10% fat kcal) and changes in meal patterns measured after long-term maintenance on the HF diet.


RESULTS
Rats fed the HF diet had a significant 50% increase in meal frequency compared to rats fed the LF diet; in addition, there was a significant reduction in meal size (32%) and inter meal interval (38%) consistent with induction of satiation. After 8 weeks on the HF diet, these parameters tend to approach those of rats maintained on the LF diet. There was a significant 56% decrease in the activation of neurons in the NTS in response to intragastric gavage of lipid in rats maintained for 8 weeks on the HF compared to LF diet.


CONCLUSIONS
Dietary fat alters meal patterns consistent with induction of a short-term satiety signal. This signal is attenuated with long-term exposure to dietary lipid, in the absence of ingestion of additional calories or changes in body weight. This adaptation of short-term satiety might contribute to diet-induced obesity.
Paulino
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G
Department Anatomy, Physiology and Cell Biology, UC Davis School of Veterinary Medicine, CA, USA.
Darcel
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N
Tome
D
D
Raybould
H
H
D000222:Adaptation, Physiological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001823:Body Composition / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005247:Feeding Behavior / Q000502:physiology; D005518:Food Preferences / Q000187:drug effects; D008055:Lipids / Q000494:pharmacology*; D008297:Male; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012527:Satiation / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
D008055:Lipids; D016760:Proto-Oncogene Proteins c-fos