circadian rhythm and time-restricted eating
Our personal sense of health changes throughout the day with our circadian rhythm. In the morning we hope to feel well-rested and fully digested, while during the day, healthy is more about not being hungry and being productive. By the time we go to bed, being able to fall asleep quickly and easily is important. Our circadian rhythm, the 24-hour cycle in physiological processes, both impacts and is impacted by our health. When we eat within a smaller window of time we can greatly benefit our health and wellbeing through influencing our circadian rhythm and the associated processes.
“Our modern lifestyles see us eating throughout the day and the night, causing insulin resistance and inflammation, removing the satiety effect of leptin, which leads to further feeding, usually as snacks containing simple sugars, which further increase fat storage and tissue inflammation.”
key benefits of time-restricted eating
According to recent research, time-restricted eating (TRE) improves health and longevity outside of calories or diet composition (Yes. You read that right! If you aren’t ready to change what you are eating, start with when you are eating).
Obesity and Metabolic Syndrome: Pour sleep impacts our health in many ways including our weight and our tendency toward metabolic syndrome! A recent study showed that TRE may have important applications for people with impacted circadian rhythms (shift workers, elderly etc.), and could result in weight loss and a reduction in metabolic issues, such as increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels. Even when there wasn’t weight loss, studies have shown TRE positively impacts blood pressure, insulin sensitivity, blood biomarkers, and oxidative stress. Other studies have confirmed these benefits and have shown TRE within a 6-hour window without reducing calories or losing weight also reduces evening appetite.
For an added impact, this study suggests we train in a fasted state. “While training of any kind promotes better insulin sensitivity, training in the fasted state enhances this effect. This study found that relatively high-intensity “cardio” performed while fasted increased subjects’ insulin sensitivity beyond the group who did the same training after a carb meal, even in the context of a normally obesogenic high-fat, high-carb diet,” states Mark Sisson, from Mark’s Daily Apple.
Gut Health and Inflammation: Multiple sclerosis (MS) is an autoimmune disease that is believed to have a person's diet as a potential contributing factor. In a pilot clinical trial on MS patients, TRE protectively altered the gut flora and decreased inflammation. Time-restricted eating has been shown to increase gut bacteria richness in species that have previously been shown to promote health in the colon.
Cardiovascular Health: An American Heart Association meta-analysis concluded limiting the number of hours of eating during the day or maintaining overnight fasting (e.g.TRE) was beneficial for maintaining cardiovascular health.
Autophagy and Neurodegenerative Diseases: Autophagy, recycling damaged cells (autophagy blog here), is reduced in the presence of insulin, so those with insulin resistance, pre-diabetes, and diabetes have suppressed autophagy and age faster. TRE, on the other hand, enables us to achieve the rates of autophagy of a younger individual by impacting our insulin sensitivity.
Research has focused specifically on the way fasting promotes autophagy in the brain, suggesting that it could be an effective way to lower the risk of neurodegenerative diseases like Alzheimer’s and Parkinson’s! Studies have shown that TRE can protect neurons against oxidative and metabolic stress of these neurodegenerative disorders (these effects are accentuated by physical exercise and intellectual activity). TRE (and exercise), also induces mitochondrial biogenesis, which is critical for the formation of synapses in developing hippocampal neurons and the maintenance of synapses in the hippocampus of adult mice...another plus for neurodegenerative disorders.
Tumor Growth: An important 2016 study with a large cohort of breast cancer patients, demonstrated a night-time fast of 13 hours or more was associated with a 36% reduction in breast cancer recurrence!
As we've stated, positive metabolic changes associated with TRE includes improved blood sugar regulation. An analysis of patients with breast cancer found that, compared with women whose HbA1c (3 month blood sugar average) was less than 6.5%, the risk of all-cause mortality was twice as high in women whose HbA1c was 7.0% or more.
Notably, circadian rhythm misalignment has been linked to increased risk of many cancers, as evidenced by the well-documented association between shift work and increased risk of breast cancer, therefore, we can theorize that “when we eat” could likely impact the chance of a number of types of cancers through its connection to our circadian rhythm.
make a plan for time-restricted eating
According to Dr. Panda, Ideally the window of eating ends by 5, 6, or 7 PM. Fasting for 10-14 hours allows us to give our gut a break from processing food. When the fasting is timed so there are 3-4 hours of no eating before bed, our sleep may even be benefited.
“There are benefits with time-restricted eating even when not following the above plan, so find a window you think you can embrace, and give it a try. This doesn’t need to be an everyday deal either, so you may want to start with just weekdays or every-other-day etc.”
Whether you are not ready to give up your Diet Coke or are happy with what you are eating, but want an added boost to your health…time-restrict eating could be an easy-to-implement next step!!
be part of a study by taking pictures
If you are thinking of giving time-restricted eating a try, there is an app that can both help you and help research! Dr. Panda's mobile app-based study of time-restricted eating is available for those that are at least 18 years of age. Just go to myCircadianClock.org.
Just a reminder that you can take all kinds of rabbit trails to learn more about this topic by clicking on the blue words.
Jay and me modeling our Change It Up Wellness Shirts!
Wendy Dellis is a certified wellness coach. She joins years of training and work in the area of behavior change, experience as a fitness instructor and run club coordinator with a passion for adventure and people. She lives in Minnesota with her husband, Jay, and two sons.
The information contained on this page is for general information purposes only. Nothing here should be construed as medical or healthcare advice, but only topics for discussion. No physician-patient relationship exists; please consult your physician before making changes in diet or lifestyle.