Updated Approach to Fasting

Fasting or early time restricted feeding is a treatment approach for chronic fatigue syndrome and fibromyalgia

Fasting is still relevant for ME/CFS and Fibromylagia…

The word on fasting as a dietary strategy has exploded since I first wrote about it in 2014. (Read that first if you haven’t already.)

Intermittent fasting, 5:2 diets, water-only fasts, every other day fasts, 16/8 fasts, warrior diets, calorie restriction diets… All of these are based on the same principles of fasting yet are varied in their methods. Extremely varied in their methods!

Fasting not working for you? Consider…

Fasting is most effective when also considering time of day.

In our genome, there are CLOCK genes which produce proteins that help maintain diurnal (day active) patterns—the circadian rhythm. The notion of a night owl and an early riser may in fact be genetically programmed. Liver cells, fat cells, and muscle cells contain a large percentage of these proteins controlled by CLOCK genes. This means simply that proteins are produced in a 24-hour oscillation, creating a rhythm.

For example, the insulin protein is more abundantly expressed in the morning than at night. This translates to less tolerance of sugars in the evening. With less insulin there is a propensity to fat storage in the evening. This is the main reason eating late at night is ill advised for maintaining weight. The lack of metabolic flexibility also wreaks havoc on the health of chronic shift workers.

In mammals, there is an early daytime peak of proteins involved in DNA repair, and a nighttime peak of proteins associated with protein breakdown, transport, and cellular repair. Another example, in humans there is a peak of growth hormone release in the evening and during sleep. This is believed to aid in tissue repair from the day’s activity. Sleepless night lead to sore muscles and pain? Now you know why.

This opens the door to clinical trials that account for time specific treatment interventions. These are already underway. Examples include, controlling blood sugar before and after breakfast in type II diabetics; administering chemotherapy drugs to cancer patients at a certain time of day to enhance drug effect and minimize side effects; and the best time of day to administer anti-hypertensive drugs to those with high blood pressure to prevent cardiac events (answer: the evening).

Oxidative Stress is Cyclical

Even more interesting is the circadian rhythm of oxidative stress. Proteins that regulate the balance of oxidative stress of the red blood cell and mitochondria have been shown to follow a circadian pattern. In blood, the master antioxidant glutathione was even found to have a diurnal regulation. This may be one reason why decades of research in antioxidants has been a mixed bag. Could it be that administration of antioxidants at a certain time of day are most effective to reduce excessive oxidative stress?

Intermittent fasting not effective for you when skipping breakfast? Try instead to eat to optimize circadian rhythms.


This new approach, and one that I now routinely follow, is known as early time restricted feed, eTRF, and is based on principles of the new discipline of chrono-nutrition. A randomized, cross over trial of pre-diabetic men showed marked results after 5 weeks of eTRF. This included improved insulin sensitivity, blood pressure, sleep, oxidative stress, and appetite control. Most striking, these effects were observed in absence of weight loss.

eTRF fig.jpg

Left, similar recommendations as I previously described in 2014. Right, new eTRF strategy for fasting based on current circadian evidence. Graphic taken from Sutton EF et al. (2018)

Practical Tips

If the notion of fasting of any kind means worsening of symptoms for you, full stop. As I mentioned in my 2014 post, fasting of any kind should not be undertaken until first establishing a dietary baseline. If you suffer from reactive hypoglycemia, fasting will not be a good experience until better blood sugar control. A hunger-free diet consisting of low carb, high fat, anti-inflammatory foods is a good place to start.

I can help with diet plans via online consultations.

My last recommendations suggested most fasting be done during sleep. At first glance it seems this method is more difficult. That’s not necessarily the case. Here aim for a 6-hr feeding window, with dinner before 3 p.m. Implement this strategy a couple of times a week at first. You may even open the window to 8-hr as it better fits your social schedule and routines. In general, intermittent fasting is always flexible.

Remember that insulin sensitivity is most robust in the morning. Because of this have your largest meal at breakfast. If you are going to include more carbohydrate foods, include them earlier in the day.

If the skipping breakfast methods of IF is working well for you, no need to change it.

Why fasting still makes sense for ME/CFS and other chronic conditions:

  • reduces oxidative stress

  • improves sleep

  • improves insulin sensitivity

  • improves appetite control

  • preserves lean mass

  • reduces blood pressure, if hypertensive

  • weight loss with long term compliance, if overweight

  • remodels the gut microbiome

  • increases authophagy (cellular housekeeping)


Nagy A. & Reddy A. (2018) Redox clocks: Time to rethink redox interventions. Free Radical Biology and Medicine. Vol 119:3-7.

Reddy A.B. (2016) Redox and Metabolic Oscillations in the Clockwork. In: Sassone-Corsi P., Christen Y. (eds) A Time for Metabolism and Hormones. Research and Perspectives in Endocrine Interactions. Springer, Cham.

Sutton EF, et al. (2018) Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Clinical and Translational Report. 27(6): P1212-1221.E3.

Johnston JD et al. (2016) Circadian Rhythms, Metabolism, and Chrononutrition in Rodents and Humans. Adv Nutr. 7(2):399-406.