Intermittent fasting isn’t just a come and go health fad. Isagenix® Cleanse Days have been a tool to support overall health and weight loss since the company’s inception in 2002. And over the past decade, there has been a huge jump in research behind this practice.

At Isagenix, we see the benefits of nutritionally-supported intermittent fasting firsthand, with people experiencing long-term weight loss and weight maintenance, along with other noticeable improvements in physical and mental performance. Just look at some of the incredible transformations from our IsaBody Challenge® participants and 100 Pound Club members!

Emerging findings from human studies indicate that fasting may provide effective strategies to reduce weight, delay ageing and optimise health (1). Weight loss is the benefit that receives the most attention, however, there are a few other good reasons to make regular Cleanse Days part of your routine.

What are the physiological benefits of intermittent fasting?

In a recent review paper, human studies revealed that when intermittent fasting was combined with caloric restriction, benefits were observed in circulating blood lipids, including total cholesterol and triglycerides, improvements in glucose homeostasis (better blood sugar control) and an increased resistance of the brain and heart to effects of stress (2). The authors also discussed that in animal studies, intermittent fasting appears to have a protective effect on the central nervous system (CNS).

The best protocol for intermittent fasting is…

Reviewing the science of intermittent fasting is difficult for us professionals, let alone the average health and wellness enthusiast. That’s because there are several different fasting patterns that researchers tend to study, ranging from 16 hours to 48 hours, and even alternate day fasting. In one particular study, the authors note that intermittent fasting of up to two consecutive days (like Isagenix single or double Cleanse Days) was the most lifestyle ‘friendly’ protocol and it didn’t lead to ‘compensatory over-consumption’ that was seen with some other fasting protocols (2). There was instead a ‘carry-over’ effect where self-regulated food intake was actually less on non-fasting days.

How will intermittent fasting impact muscle mass?

Some scientists theorised that intermittent fasting may exert a protective benefit on muscle tissue, but after reviewing the human studies looking at fasting on body composition, it appeared that intermittent fasting could have a negative effect on muscle tissue unless adequate protein and exercise were a focus on non-fasting days (3).

To negate this, choose IsaLean™ Shake or IsaLean™ PRO, which deliver between 24-36 g of high-quality protein, respectively. Consuming a convenient source of protein at regular intervals throughout the day is an important factor when it comes to improving the retention of fat-free mass, as the research has shown.

What does this all mean?

When deciding to incorporate a single or a double Cleanse Day into your regular routine, know that the most recent scientific literature supports the one and two-day intermittent fasting protocols, as well as providing the necessary nutrition support to maximise muscle retention. So be sure to include IsaLean Shake or IsaLean PRO on your Shake Days. And while it’s nice to read about the science, it’s even better to see how everyday Aussies and Kiwis have found success by following our simple nutrition system.

* If you are pregnant, breastfeeding, diabetic, on medication, have a medical condition or are beginning a weight loss program, consult your GP before using Isagenix products or making any other dietary changes. Discontinue use if adverse event occur.



  1. Harvie MN, Pegington M, Mattson MP, et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. Int. J. Obes. (Lond). 2011; 35:714–727.
  2. Mattson MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease processes. Ageing Res Rev. 2016;39:46-58.
  3. Harvie M, Wright C, Pegington M, et al. The effect of intermittent energy and carbohydrate restriction v. daily energy restriction on weight loss and metabolic disease risk markers in overweight women. Br. J. Nutr. 2013b:1–14.