The homeostatic feeding response to fasting is under chronostatic control

ABSTRACT

Eating behavior is controlled by the energy needs of the organism. The need to provide a constant supply of energy to tissues is a homeostatic drive that adjusts feeding behavior to the energetic condition of the organism. On the other hand, food intake also shows a circadian variation synchronized to the light-dark cycle and food availability. Thus, feeding is subjected to both homeostatic and circadian regulation mechanisms that determine the amount and timing of spontaneous food intake in normal conditions. In the present study we contrasted the influence of the homeostatic versus the chronostatic mechanisms on food intake in normal conditions and in response to fasting. A group of rats was subjected to food deprivation under two different temporal schemes. A constant-length 24-h food deprivation started at different times of day resulted in an increased compensatory intake. This compensatory response showed a circadian variation that resembled the rhythm of intake in non-deprived animals. When subjected to fasting periods of increasing length (24–66 h), the amount of compensatory feeding varied according to the time of day in which food was made available, being significantly less when the fast ended in the middle of the light phase or beginning of the dark phase. These oscillatory changes did not have a correlation with variations in the level of glucose or β-hydroxybutyrate in the blood. The results suggest that the mechanism of homeostatic compensation is modulated chronostatically, presumably as part of the alternation of catabolic and anabolic states matching the daily cycles of activity.

KEYWORDS:

• Food intake
• fasting
• circadian rhythm
• energy homeostasis
• chronostasis

Acknowledgments

This work was supported by grants 20062096 and 20070397 from SIP IPN to IV and PAPIIT IN-205917 to RAR. Thanks to Dr. Ellis Glazier for editing this English-language text.

Declaration of interest

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica, Universidad Nacional Autónoma de México [IN-205917];Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional [20062096 and 20070397].