Early Time-Restricted Feeding: Intermittent Fasting In Sync with the Circadian Rhythm

Posted on by Jesse Santiano, M.D.

Early Time-Restricted Feeding is Intermittent Fasting In Sync with the Circadian Rhythm

Early Time-Restricted Feeding (eTRF) is a form of intermittent fasting where the meal period starts in the morning and lasts for 6 to 8 hours. For example, an 8-hour period of eating will begin at 7 am, and then the last meal may be at 3 pm, and another is from 9 am until 3 pm for 6 hours. During the meal period, one to two meals may be consumed.

In the fasting period, unsweetened liquids are allowed, like water, black tea, or coffee.

eTRF provides eating flexibility for individuals who prefer to eat earlier in the day rather than wait until around noontime or late afternoon.

What is the Circadian Rhythm?

The circadian rhythm or biological clock is a naturally occurring 24-hour cycle that governs body processes like hormonal secretion. An example is the body is more sensitive to insulin in the morning.

Besides, the thermic effect of food or the heat generated as food is digested is higher in the morning. This suggests that human metabolism is optimized for food intake in the morning.

Insulin

Insulin is the hormone produced by the pancreas that rises after eating. It stores amino acids, fatty acids, and glucose for maintenance, repair, and energy source. 

Normal function dictates that the pancreas has to be responsive to food presence and produce the right amount of insulin. The muscles and liver should also be responsive to insulin (insulin sensitive) to accept and store the glucose circulating in the blood.

In diabetes, the muscles and the liver do not respond well to insulin, leading to a high blood sugar level or glucose in the blood. A condition called insulin resistance. In response, the pancreas produces more insulin to “push” the glucose into the muscles. A state called hyperinsulinemia. However, insulin resistance and hyperinsulinemia lead to more problems. Insulin resistance should be eliminated, and intermittent fasting is an answer. 

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Circadian Rhythm

Benefits of Intermittent Fasting (IF)

Human studies about intermittent fasting show that IF:

  1. Decreases body weight
  2. Decreases insulin levels and improves insulin sensitivity
  3. Decreases blood pressure
  4. Reduces inflammation
  5. Reduces appetite
  6. Improves lipid profiles resulting in higher HDL and lower triglycerides

Early Time-Restricted Feeding (eTRF)

The human studies referenced below show that eTRF:

  1. Reduces Oxidative Stress and inflammation that causes many diseases
  2. Reduces Appetite in the Evening
  3. Increase the brain-derived neurotrophic factor (BDNF). BNDF promotes the growth, development, and survival of brain cells.
  4. Increase in Sirtuin 1 (SIRT1). SIRT1 promotes insulin secretion and action, increases fat metabolism, and protects against inflammation, oxidative stress, and DNA damage. It also increases telomere stability to continue normal cell division in aging and extends the lifespan.
  5. Have anti-aging effects in humans by increasing autophagy. Autophagy is a process of recycling old and useless cells to make new ones. It can protect against chronic diseases such as diabetes, heart disease, cancer, and neurodegenerative diseases.
  6. Elevate ketone levels to reduce oxidative damage and preserve muscle mass.

Take Away Message for Early Time-Restricted Feeding

Intermittent fasting is flexible. A feeding period of 6 to 8 hours can be started in the morning, and the fasting period can start late in the afternoon and overnight.

This eating pattern synchronizes with the circadian pattern of insulin secretion and effectiveness and provides several health benefits.

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Related Readings:

  1. Christmas Gifts that Prioritize Health
  2. Getting Ready to Celebrate the Holidays
  3. What is Insulin Resistance? 
  4. Hyperinsulinemia
  5. Drugs that Cause Insulin Resistance
  6. Autophagy – How to Recycle Yourself
  7. Fasting and Exercise for Fatty Pancreas
  8. How to do Intermittent Fasting
  9. A Case Report of 3 Diabetic Patients that are Weaned Off Insulin
  10. The Good and Faithful Servant
  11. The Surprising Benefits of Sweating
  12. 10 Unbelievably Easy Ways to Screw Up Intermittent Fasting!
  13. The Game-Changing Uses of KAATSU

References:

  1. Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Sutton EF, Beyl R, Early KS, Cefalu WT, Ravussin E, Peterson CM. Cell Metab. 2018 Jun 5;27(6):1212-1221.e3. doi: 10.1016/j.cmet.2018.04.010. Epub 2018 May 10.
  2. Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans. Humaira Jamshed, Robbie A. Beyl, Deborah L. Della Manna, Eddy S. Yang, Eric Ravussin, Courtney M. Peterson
  3. Early Time-Restricted Feeding Reduces Appetite and Increases Fat Oxidation But Does Not Affect Energy Expenditure in Humans. Ravussin E1, Beyl RA1, Poggiogalle E1,2, Hsia DS1, Peterson CM. Obesity (Silver Spring). 2019 Aug;27(8):1244-1254. doi: 10.1002/oby.22518.

Image Credits:

Circadian Rhythm By NoNameGYassineMrabetTalk✉ fixed by Addicted04 – The work was done with Inkscape by YassineMrabet. Pieces of information were provided from “The Body Clock Guide to Better Health” by Michael Smolensky and Lynne Lamberg; Henry Holt and Company, Publishers (2000). The landscape was sampled from the Open Clip Art Library (Ryan, Public domain). Vitruvian Man and the clock were sampled from Image:P human body.svg (GNU license) and Image: Nuvola apps clock.png, respectively., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=3017148

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