Is fasting good for you?

For the majority of us, Yes!

Intermittent and prolonged nightly fasting have multiple positive effects on the body, including reduced oxidative stress, improved biomarkers of disease and preservation of learning and memory. These effects have implications for several chronic diseases, in particular cardiovascular health, diabetes, obesity and cancer. It makes sense that our bodies respond favorably to fasting considering how humans evolved, with feast or famine much more common than steady access to food.

The exact mechanisms are incompletely understood, but current prevailing theory is that fasting creates a mild form of stress on the cells, similar to the stress of vigorous exercise. And we all know exercise has a multitude of positive effects on our minds, bodies and spirits!

Likewise, our bodies have a similar response:  Studies show reduced total cholesterol, triglycerides, fasting glucose, fasting insulin, interleukin-6, and tumor necrosis factor as well as an improvement in insulin sensitivity. After 12-16 hours, the body goes into ketosis, burning fat instead of relying on glucose for energy. In addition to weight loss, this phenomenon in particular has a beneficial effect on neurons and a protective effect against neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Fasting is associated with prolonged survival and vibrant health.

There are multiple ways to incorporate fasting in to your health routine: There is alternate day fasting, or one day a week fasting. Then there is a 5:2 modified fasting plan in which participants consume 20-25% of their energy expenditure on 2 consecutive days and then 5 days of the usual diet. Another version advocates 5 modified fasting days per month.

Prolonged nightly fasting for 12-20 hours is probably the least difficult to pull off and makes a lot of sense when considering our natural rhythms. I recommend eating during hours of light only to maximize our diurnal rhythm for metabolic health.  There’s a really cool diagram found in one of the articles from my references, Patterson et al (2015). Just click on the link below and look for Figure 2.

Research into the health effects of shift work demonstrate that disrupting the circadian rhythm by working nights is associated with increased risk of obesity, diabetes, cardiovascular disease and cancer, as well as alterations in hormones regulating appetite, such as leptin, gherlin and xenin.

Unfortunately, much of the available research on fasting is from animal models. More extensive human trials are needed to elucidate the exact mechanisms which underlie these associations. Fasting is contraindicated for individuals with a low body weight or history of disordered eating. 

What we do have are countless personal stories of health, vitality, energy and uplifted spirits. We can help you feel this good, too!



Collier, R. (2013). Intermittent fasting: the science of going without. CMAJ : Canadian Medical Association Journal185(9), E363–E364.

Longo, V. D., & Panda, S. (2016). Fasting, circadian rhythms, and time restricted feeding in healthy lifespan. Cell Metabolism23(6), 1048–1059.

Patterson, R. E., Laughlin, G. A., Sears, D. D., LaCroix, A. Z., Marinac, C., Gallo, L. C., … Villaseñor, A. (2015). INTERMITTENT FASTING AND HUMAN METABOLIC HEALTH. Journal of the Academy of Nutrition and Dietetics115(8), 1203–1212.