Cells - medical background

In what is yet another clue that performing Isagenix-style Cleanse Days can be profoundly good for you, nutrition scientists are now encouraging the occasional fast or skipping of meals for better health.

Fasting periodically might also bring the added benefit of ‘cleansing’ cells of junk and debris, according to researchers in a review paper published in the November issue of the scientific journal, Proceedings of the National Academy of Sciences.

“Cells possess dedicated mechanisms for the removal of damaged molecules and organelles,” the authors wrote.

Challenging the notion that a typical ‘three square meals a day’ regimen should be considered a standard of healthy eating, the authors wrote that giving cells a steady supply of nutrients in this way keeps cells in ‘growth mode.’

While in continuous growth mode, cells have little chance of going into a cleansing mode that involves a couple of mechanisms:

  • The first is a sort of molecular ‘tagging’ of proteins that targets them for recycling and re-using their amino acid building blocks by a protein degradation complex known as a proteasome.
  • The second is autophagy whereby damaged molecules and organelles are ‘cleansed’ from cells by lysosomes, those membrane-enclosed organelles full of acids and digestive-like enzymes.

Among the authors of the paper were leading scientists from around the world in the field of intermittent fasting, time-restricted feeding, and calorie restriction.

They included Krista Varady, Ph.D., of the University of Illinois at Chicago (UIC), who was the lead researcher of a study evaluating the use of the Isagenix programs comprising of intermittent fasting (Cleanse Days) combined with calorie restriction (Shake Days).

The Isagenix study, in fact, was included as one of the references in the article as evidence that intermittent fasting combined with calorie restriction could lead to weight loss, which resulted in suppressed inflammation in the body.

Additional studies from Dr. Varady’s lab and those of Mark Mattson, Ph.D., of the National Institute on Aging, have shown that calorie restriction and, intermittent fasting especially, improved insulin sensitivity while boosting fat metabolism.

Furthermore, these dietary approaches could lead to the elevation of ketones in the body. Ketones are chemicals produced during the breakdown of fat and are known to provide some benefits against brain aging.

Moreover, intermittent fasting in animals has led to production of several brain-protective proteins, improved mitochondrial function, and stimulation of the activity of key antioxidant enzymes such as superoxide dismutase and catalase.

To obtain the benefits of calorie restriction and intermittent fasting, the authors advocate an eating pattern modeled after our hunter-gatherer ancestors who ate less frequently. Historically, hunter-gatherers, both ancient and modern, rarely suffered from obesity and functioned at a high level physically and mentally.

According to the authors, the pattern of ‘three square meals a day’ began only after the advent of agriculture 10,000 years ago as a result of a continual year-round food supply. “Our agrarian ancestors adopted a three meals a day eating pattern, presumably because it provided both social and practical benefits for the daily work and school schedules,” the authors wrote.

One of the contributing factors to obesity, they argued, was the adoption of sedentary lifestyles combined with multiple high-calorie meals daily.

Another cause of overeating may also be the advent of artificial light and how it affects our internal circadian clocks, which are intended to function on a daily light-dark cycle. The increase in hours awake leads to more opportunities to overeat while also interfering with the sleep/wake and fast/feed cycle that may be a key factor in regulating appetite and metabolism.

With the adoption of a dietary pattern that incorporates periods of fasting, calorie restriction, or both—such as an Isagenix program—along with exercise, healthy eating, and proper sleep, the authors suggest a number of health benefits including reduction of abdominal fat and improved metabolic and cardiovascular risk markers.


Mattson et al. Meal frequency and timing in health and disease. Proc Natl Acad Sci. 111 (47):16647–16653, doi: 10.1073/pnas.141396511