Body weight gain in rats by a high-fat diet produces chronodisruption in activity/inactivity circadian rhythm

In the last few decades, obesity has become one of the most important public health problems. Adipose tissue is an active endocrine tissue which follows a rhythmic pattern in its functions and may produce alterations in certain circadian rhythms. Our aim was to evaluate whether the locomotor activity circadian rhythm could be modified by a hypercaloric diet in rodents. Two groups were considered in the experiment: 16 rats were used as a control group and were fed standard chow; the other group comprised 16 rats fed a high-fat diet (35.8% fat, 35% glucides). The trial lasted 16 weeks. Body weight was measured every week, and a blood sample was extracted every two weeks to quantify triglyceride levels. The activity/inactivity circadian rhythm was logged through actimetry throughout the trial, and analysed using the DAS 24© software package. At the end of the experiment, the high-fat fed rats had obese-like body weights and high plasma triglyceride levels, and, compared with the control group, increased diur...