Ever had questions about whether performing “Cleanse Days” on a regular basis (once or twice a week of intermittent fasting as on an Isagenix plan) is truly healthy as a weight-loss approach? It’s clear from the testimonials and before-and-after pics that cleansing this way works wonders, but often people including health professionals have questioned, “Is it truly safe and effective?”

In 2012, Krista Varady, Ph.D., of the University of Illinois at Chicago investigated Cleanse Days performed as often as one day a week in combination with Shake Days (two high-protein IsaLean Shakes per day along with a heart-healthy meal) and found it led to significant weight loss and improvement to cardiovascular health markers (1,2). The study saw no evidence of adverse health events related to the intermittent fasting or to the use of the products (1,2).

Recently, the same lab conducted a follow-up study (not funded by Isagenix or with Isagenix products) to test a more intensive, alternate-day fasting schedule where subjects ate one day, fasted the next, and then repeated the routine (3). Even when using this more aggressive fasting schedule, according to the researchers, there were not any adverse health benefits. The researchers determined that such a nutritional plan was also generally safe.

In the new study, obese subjects followed an alternate-day fasting protocol for eight weeks. Their nutritional plan was based on the American Heart Association’s guidelines with a higher load of carbohydrates and lower levels of protein. In comparison to subjects who followed a simple, calorie-restricted diet and who did not fast, the subjects who fasted reported no greater adverse effects (3).

The study results also suggested that fasting may have had a small beneficial effect on body image perception. Interestingly, restrictive eating was moderately increased with fasting, suggesting that the diet may have helped control unrestrained eating behaviors (3).

What the research highlights is the increasing evidence of absolute health and safety of intermittent fasting regularly, or adopting Cleanse Days on a regular basis. The alternate-day fasting schedule used in the new study shouldn’t be viewed as a potential alternative or as more effective than the one-day-a-week or two-day-a-week on Isagenix plans. There’s just no need to go to this sort of extreme approach when the regular Isagenix cleansing routine is shown to be effective.

Moreover, the new research also alleviates some concerns that health professionals have had about the approach overall. These include worries about energy levels and blood sugar management, as well as potential unhealthy eating behaviors. There appears to be no evidence of any problems when adopting Cleanse Days one day a week or even a more aggressive alternate-day fasting approach to weight loss (3,4).

It’s also been demonstrated previously that a 25 percent daily restriction in calories did not increase eating disorder symptoms and had no other harmful psychological effects (5). The majority of the research has also found that intermittent fasting or alternate-day calorie restriction also reduces markers of oxidative stress in the body (1-6)

Additionally, another clinical study found no evidence of adverse health effects when evaluating use of Isagenix products and Cleanse Days after 12 months. The study, performed by Paul Arciero, Ph.D., of Skidmore College is the first to study the effects of Cleanse Days long-term.

A close look at the scientific evidence conclusively reveals that regular Cleanse Days per week—even in an aggressive fashion, but not recommended—are a safe and effective way to lose weight. On an Isagenix plan as opposed to intermittent water fasting alone, Cleanse Days also come with nourishment from Cleanse for Life, a botanical beverage, that supports the body’s key antioxidant and detoxification process. In addition, the Isagenix system allows for use of key nutritional tools like Isagenix Snacks and IsaDelights to support blood sugar control and help through hunger pangs. The end result is a well-designed, clinically validated system.

So cleanse happily, and lose weight worry-free.


  1. Klempel MC, Kroeger CM, Varady KA. Alternate-day fasting (ADF) with a high-fat diet produces similar weight loss and cardioprotection as ADF with a low-fat diet. Metabolism 2013;62:137-43.
  2. Varady KA, Bhutani S, Church EC, Klempel MC. Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults. The American Journal of Clinical Nutrition 2009;90:1138-43.
  3. Hoddy KK, Kroeger CM, Trepanowski JF, Barnosky AR, Bhutani S, Varady KA. Safety of alternate-day fasting and effect on disordered eating behaviors. Nutrition Journal 2015;14:44.
  4. Bhutani S, Klempel MC, Kroeger CM, Trepanowski JF, Varady KA. Alternate-day fasting and endurance exercise combine to reduce body weight and favorably alter plasma lipids in obese humans. Obesity 2013;21:1370-9.
  5. Williamson DA, Martin CK, Anton SD et al. Is caloric restriction associated with development of eating disorder symptoms? Results from the CALERIE trial. Health Psychology 2008;27:S32.
  6. Johnson JB, Summer W, Cutler RG et al. Alternate-day calorie restriction improves clinical findings and reduces markers of oxidative stress in overweight adults with moderate asthma. Free Radical Biology and Medicine 2007;42:665-74.