Scientists are uncovering a fascinating relationship between circadian rhythms and food consumption. It looks as though when you eat can have a big impact on how your body metabolizes the food and on whether or not you gain weight.
It has long been clear that light exposure plays an important role in setting a number of circadian rhythms in the brain and body. A part of the brain called the suprachiasmatic nucleus (SCN), perched right beside the nerve pathways that transmit signals from the eye to the part of the brain that processes visual information, plays a central role in this process. The SCN synchronizes many of the hundreds, perhaps thousands of “clocks” throughout the body that regulate aspects of physiology that need to be coordinated with the cycle of night and day taking place outside the body.
It now seems that the parts of the body involved in metabolizing food, and, in particular, sugar, may be partly controlled by when we eat. In other words, these clocks are set by the timing of food intake. And when our pattern of eating does not match the pattern of light and dark exposure our eating and our metabolism can get dysregulated. One of the consequences of this is weight gain.
A common example of this mismatch between the two biorhythms is someone who eats almost all of his or her food after dark in the evening. This fairly common pattern seems to be associated with a greater tendency to weight gain and to elevated cholesterol and elevated blood sugar.
People who switch to eating during daylight hours can expect to see improvements in metabolism.
In a recent study by Gill and colleagues, participants were asked to restrict the timing of their caloric consumption between the hours of 06:00 and 18:00 h for up to 1 year and document the timing of meals on a mobile phone application Similar to the studies on other animals, they found a significant decrease in weight after 16 weeks of intervention. Furthermore, participants reported concurrent increases in overall energy levels and morning energy levels and decreases in hunger at bedtime.
For More Information
Broussard JL, Van Cauter E. Disturbances of sleep and circadian rhythms: novel risk factors for obesity. Curr Opin Endocrinol Diabetes Obes. 2016 Oct;23(5):353-9. doi: 10.1097/MED.0000000000000276. PubMed PMID: 27584008; PubMed Central PMCID: PMC5070789.
McHill AW, Wright KP Jr. Role of sleep and circadian disruption on energy expenditure and in metabolic predisposition to human obesity and metabolic disease. Obes Rev. 2017 Feb;18 Suppl 1:15-24. doi: 10.1111/obr.12503. Review. PubMed PMID: 28164449.
Smartphone app reveals erratic diurnal eating patterns in humans that can be modulated for health benefits. Cell Metab2015; 22: 789–798., .