Cleanse Days, or nutritionally-supported intermittent fast days, are kind of like ‘secret sauce’ when it comes to the results and stories that we hear about daily. They’re not only important for those on a weight loss mission, but are also key to healthier ageing and better mental clarity (1). This often leads to questions like “Is it better to cleanse for one or two days at a time?” and “When exactly does a ‘double cleanse’ start and finish?” or “Should I exercise on a Cleanse Day?”

So, grab a cuppa (or a warm mug of Cleanse for Life™!) and let’s tackle each question one by one.

Q: Is it better to cleanse for one or two days?

We take pride in offering flexibility when it comes to our health solutions, and our approach to Cleanse Days is no different, including either single Cleanse Days, double (two consecutive) Cleanse Days or gentle cleansing (a daily single serve of Cleanse for Life).

There’s no single perfect way to cleanse – it’s really whatever fits you; your own schedule, health goals and preferences. For individuals looking for an accelerated weight loss path, double cleanse days may provide more opportunity for burning fat as a primary fuel for longer, as prolonged fasting encourages our body to ‘dig deeper’ into fat stores for energy.

However, in all our clinical trials, participants followed a 30-day system with single Cleanse Days, and the results have been remarkable. The UIC study noted that the Isagenix 30-day System (compared to a traditional ‘Heart-Healthy’ wholefoods diet, including one day per week of intermittent fasting) led to 56% greater reduction in average weight loss, 47% greater reduction in average body fat loss, twice as much visceral fat loss, and small but significant improvements in heart health markers (2). These findings were mirrored in the follow-up study at Skidmore College (3).

So, one day or two days? Whatever works (and feels) best for you.

Q: When does a double cleanse start and finish?

This question often comes from those wondering whether they are fasting beyond 48 hours, the results of which are not ideal for preserving lean mas (aka muscle). Typically, a double cleanse starts on breakfast of the first day (e.g. Monday morning) and finishes on the second evening (e.g. Tuesday night), with the first meal being the breakfast shake (e.g. Wednesday morning). Ideally, the evening meal prior to entering a double cleanse (e.g. Sunday night) should be an IsaLean™ Shake, to prime the body with a light yet nutrient-dense meal.

Note that the fasting state begins at around 12 to 18 hours after your last meal, so a 48-hour fast (double cleanse) technically starts from the first morning of your Cleanse Day and ends with the breakfast shake on the third morning.

Q: Should I exercise on a Cleanse Day?

As long as you’re not attempting to run a marathon or complete a heavy ‘leg day’ workout, you may find that light-to-moderate exercise can help to generate even better results. A recent study revealed that exercise while fasting may help to promote better weight loss, body composition and improvements in cardiovascular disease risk factors compared to fasting or exercise alone (4). Another study looked at muscle damage during a water-only fast (compared to a control group who exercised in the ‘fed’ state). The researchers found that fasting had no effect on exercise-induced muscle damage or muscle recovery (5). Light exercise can also have a mild appetite suppressant effect and may help to manage hunger on Cleanse Days

Exercise on your Cleanse Days may include yoga, walking, a light bike ride, a gentle swim, a stretching session or low-impact home workout. Exercise can help you relax, take your mind off eating and incorporate lower-intensity workouts with your usual training. However, as always, listen to your body and don’t overdo it.


  1. Mattson MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease processes. Ageing Res Rev. 2017;39:46–58. doi:10.1016/j.arr.2016.10.005
  2. Klempel MC, Kroeger CM, Bhutani S, Trepanowski JF, Varady KA. Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women. Nutr J. 2012 Nov 21;11:98.
  3. Arciero PJ, Edmonds R, He F, Ward E, Gumpricht E, Mohr A, Ormsbee MJ, Astrup A. Protein-Pacing Caloric-Restriction Enhances Body Composition Similarly in Obese Men and Women during Weight Loss and Sustains Efficacy during Long-Term Weight Maintenance. Nutrients 2016, 8(8), 476; doi: 10.3390/nu8080476
  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. Dannecker EA, Liu Y, Rector RS et al. The effect of fasting on indicators of muscle damage. Experimental gerontology 2013;48:1101-6.
  6. Bachman JL, Deitrick RW, Hillman AR. Exercising in the Fasted State Reduced 24-Hour Energy Intake in Active Male Adults. J Nutr Metab 2016; Volume 2016, Article ID 1984198, 7 pages.