Time Restricted Eating: Lose Weight & Improve Sleep
In America, obesity has reached epidemic levels. At the time of writing, The Centers for Disease Control reports that 37.9% of Americans are obese and 70.7% are overweight! The majority of unhealthy people are metabolically broken. They sleep too little, eat too much, and stress themselves too much.The over consumption of sugar, fat, and processed food have played their role. But I believe a dysfunctional circadian rhythm is at the root of these problems. If we can fix our circadian rhythm, then we can get one step closer to solving the problem.
For the last 300,000 years, we have evolved on this planet under the influence of a light and dark cycle. Before grocery stores and restaurants, food availability was limited to the daytime hours. The limited access to food and sunlight programmed the human body to follow a 24-hour circadian rhythm (seen below). This rhythm is responsible for our sleep-wake cycle, cellular function,and behavior.
Modern humans face an uphill battle. Our current environment interferes with our natural circadian rhythm. It persuades us to sleep little and consume more. A lack of sleep combined with an erratic eating schedule can dampen the robustness of our rhythm and cause metabolic dysfunction. The digestive system, cardiovascular system, immune system, and certain brain regions all rely on a functional circadian rhythm (1). Therefore, a misaligned circadian rhythm puts us at a greater risk for obesity, diabetes, and disease (1,,2 ,3 ).
How Do We Fix A Broken Rhythm?
To reset and realign a circadian rhythm we must look at our sleep and eating schedule. An optimal rhythm requires us to sleep 7.5 to 9 hours a night. We should fall asleep between 9 and 11 pm and wake up around 6 to 8 am. Granted, not everyone can adhere to this schedule due to work, family, and social life. But, if you are serious about your health then you should do everything in your power to get the recommended amount of sleep.
Our digestive system is influenced by our circadian rhythm. It evolved to function at certain times of the day and to recover at other times of the day. Most likely we evolved to eat during the day and fast at night. After all, breakfast does stand for “breaking a fast”. Unfortunately, we are no longer following this rhythm. Most of us eat from the time we wake up to the time we go to bed (4). We give our digestive system little time to recover. This constant eating leads to excessive calorie consumption and weight gain. Thus, to reduce calorie consumption and improve digestion, we should shorten our eating window.
How Long Should I Eat For?
Studies in mice have shown that an eating window of 8-12 hours can improve circadian rhythm and is associated with reduced body fat, longer sleep duration, increased endurance, and reduced inflammation (4,5). In one of the studies, two groups of obese mice were fed a high fat-sugar diet containing the same amount of calories. The only difference was that one group had to consume their meals in a nine hour window, while the other group had no restrictions.
The group with no time restraints became obese while the other group stayed lean and fit. But do these benefits pertain to humans? To test this theory, Shubhroz Gill and Satchidananda Panda launched a study. The study took overweight individuals and restricted their original eating window from >14 hours a day to a self-selected 10-12 hours a day.
The study required the participants to follow the eating strategy for 16 weeks, but didn’t require them to make any changes to their diet. They recorded their food intake through a smart phone application (hence the name of the study: A smartphone app reveals erratic diurnal eating patterns in humans that can be modulated for health benefits). Over the 16 weeks, the subjects lost an average of 7.2 lbs. The participants reported improved sleep, hunger, and energy levels. By the end of the study all of the participants expressed interest in continuing the eating pattern. After 36 weeks of the intervention, the participants maintained weight loss, sleep, and had more energy (4). Pretty cool, right?
A caloric deficit is essential for weight loss and health. Time restricted eating is another tool we can use to achieve it. Based on my client’s experiences, I have found that when you follow a time restricted protocol, you tend to sleep better and have more energy the following day. TRE combined with adequate sleep will normalize your circadian rhythm and give your cells the rest and recovery they deserve.