Have you ever noticed that your appetite seems more manageable following a Cleanse Day? Researchers have noticed this unexpected effect, too, and are now investigating the science behind how Cleanse Days might help to reset your appetite.

An Isagenix Cleanse Day is a type of nutritionally supported fast that’s designed to help you feel nourished and energized. On Cleanse Days, the goal is to significantly limit the calories you consume for a period of one or two days each week while receiving nourishment from Cleanse for Life®. There are no diuretics or laxatives involved – Cleanse Days are all about allowing your body a chance to rest and recharge.

Scientists refer to the basic concept behind Cleanse Days as intermittent fasting, and an increasing number of studies have highlighted its benefits for supporting weight loss as well as benefits for cellular health and metabolism (1-3). But researchers have recently noticed an unexpected benefit of intermittent fasting for helping to manage appetite.

Unexpected Results

It’s common to feel hungry or struggle to manage appetite when following a typical weight loss diet. In fact, feeling hungry is one of the main reasons that people offer for quitting a diet or giving up when they are trying to lose weight (4, 5). This well-known relationship between ordinary dieting and an increase in hunger is why researchers took notice when volunteers participating several related weight loss studies reported that they felt less hungry by the end of the study (6, 7).

The researchers, based at the University of Illinois at Chicago, had been studying the benefits of intermittent fasting for health and weight loss. After noticing that many of the people who participated in their research experienced benefits for managing appetite, they decided to investigate further with a study designed to measure changes in some of the hormones that influence appetite during weight loss.

Appetite Hormone Reset

There are many factors that influence a person’s feelings of hunger and fullness, but appetite-regulating hormones including ghrelin and peptide YY (PYY) are some of the key players. Ghrelin signals hunger and works to increase appetite, while PYY helps to promote fullness and satisfaction after a meal.

The University of Illinois at Chicago team conducted a 10-week study to evaluate the effects of intermittent fasting during weight loss on hunger, fullness, and appetite-regulating hormones (8). Similar to their earlier studies that involved intermittent fasting, the participants lost a significant amount of weight. However, the study participants did not experience an increase in hunger. They also reported feeling greater levels of fullness and satisfaction after eating.

The improvements in appetite control that study volunteers experienced mirrored the changes that researchers observed in appetite-regulating hormones. Typically levels of the appetite-stimulating hormone ghrelin increase after weight loss, but the participants had no change in ghrelin levels (9). Additionally, the study volunteers had an increase in the level of the fullness-related hormone, PYY.

Research into the appetite regulation benefits of intermittent fasting is still in its early stages, but the results of this study confirm what many people who regularly complete Cleanse Days may have noticed for themselves – Cleanse Days might help to reset your appetite.


  1. 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.
  2. Halberg N, Henriksen M, Söderhamn N, Stallknecht B, Ploug T, Schjerling P, Dela F. Effect of intermittent fasting and refeeding on insulin action in healthy men. J Appl Physiol. 2005 Dec;99(6):2128-36.
  3. Bergamini E, Cavallini G, Donati A, Gori Z. The role of autophagy in aging: its essential part in the anti-aging mechanism of caloric restriction. Ann NY Acad Sci. 2007 Oct;1114:69-78.
  4. Hetherington MM, Cunningham K, Dye L, Gibson EL, Gregersen NT, Halford JC, et al. Potential benefits of satiety to the consumer: scientific considerations. Nutr Res Rev. 2013;26:22e38.
  5. Stubbs J, Brogeli D, Pallisoter C, Avery A, McConnon A, Lavin J. Behavioural and motivational factors associated with weight loss and maintenance in a commercial weight management programme. Open Obes J. 2012;4:35e43.
  6. Klempel MC, Bhutani S, Fitzgibbon M, Freels S, Varady KA. Dietary and physical activity adaptations to alternate day modified fasting: implications for optimal weight loss. Nutr J. 2010;9:35.
  7. Bhutani S, Klempel MC, Kroeger CM, Aggour E, Calvo Y, Trepanowski JF, et al. Effect of exercising while fasting on eating behaviors and food intake. J Int Soc Sports Nutr. 2013;10:50.
  8. Hoddy KK, Gibbons C, Kroeger CM, Trepanowski JF, Barnosky A, Bhutani S, Gabel K, Finlayson G, Varady KA. Changes in hunger and fullness in relation to gut peptides before and after 8 weeks of alternate day fasting. Clin Nutr. 2016 Dec;35(6):1380-1385. doi: 10.1016/j.clnu.2016.03.011.
  9. Cummings DE, Weigle DS, Frayo RS, Breen PA, Ma MK, Dellinger EP, et al. Plasma ghrelin levels after diet-induced weight loss or gastric bypass surgery. N Engl J Med. 2002;346:1623e30.