We expend much time and effort focusing on the quality and quantity of food consumed. There's no question that switching out processed foods for whole, organic foods is key to good nutrition. So is paying attention to how much one eats.
But we don't place enough emphasis on the frequency and circadian timing of meals. Recent research investigated the role that our evolutionary body clock has on when we should eat. For most of human history, our lifestyles have followed a natural light/dark rhythm with most of our activity and food consumption occurring during daylight and not much other than sleep during darkness.
Two groups of mice were fed a poor-quality, high-fat diet (akin to the typical American diet). Both groups received the same number of calories. One group ate whenever they wanted in 24 hours, while the other ate only during an 8hr window in sync with a mouse's circadian rhythm. Results:
8hr feeding time: optimal body composition, motor coordination improved
24 hr feeding time: overweight, diabetic, hyperinsulinemia (high insulin levels in the blood), fatty liver disease, inflammation
A follow up study found that the time-restricted mice remained lean and healthy, even when their feeding time was increased to a 9-12 hour window and they were allowed "weekend cheats." Halfway through the study, the unrestrained eaters were switched over to a 9-12hr feeding window and they began to shed the extra weight they had gained via non-time-restricted feeding.
Eating by our natural body clock means that consumption happens when the body is more efficient at breaking down foods. The metabolic system evolved to make fuel and energy available at specific times of the day. Once daylight fades into nighttime and feeding ends, we enter a unique alternative metabolic phase. In the nonfeeding state, the body's process of regeneration and repair begins. Cells recycle their contents to promote optimal health and prevent disease. Researchers found that 12- 16 hours of non-feeding reduces excess body fat while lowering levels of insulin and blood sugar. He also found that it's healthful for the body to impose the mild cellular stress of 12-16 hours of non-feeding, as it strengthens cells' ability to adapt and cope with more severe stresses like disease and aging.
The easiest and most basic plan is to feed within a 12 hour window, ideally in sync with the light/dark cycle. Increasing the nonfeeding time to anywhere between 12 and 16 hours enhances the health benefits of the regenerative period.
What are some of your experiences with time restricted eating (sometimes called intermittent fasting)?