Kayla Waler, MFT Intern at Potentia: So, we’ve recently tackled pertinent topics such as Paleo and gluten-free diets. My friends have expressed interest in a Q&A about juice fasts and cleanses. I know juice fasts and cleanses are popular, especially around certain times of the year…what can you tell me about this practice?
Megan Holt, RD, MPH, Ph(c) and Coordnator of Nutrition and Wellness at Potentia: In my experience, people tend to be interested in cleansing for one of four reasons: 1) weight loss, 2) detoxification, or 3) as a means of hitting a ‘reset’ button when they’re feeling particularly bad about their current diet or 4) for an energy boost. Cleanses usually involve one or more of these components: 1) a fast 2) some sort of product or regimen purported to remove toxins from the body, or 3) a colon cleanse.
Kayla: Let’s start by talking about fasting…
Megan: I tend to discourage fasting because it can reactivate disordered eating behaviors–whether that’s restriction or feeling out of control with food or feeling disconnected from hunger and fullness cues when one does start to eat again. I generally recommend against it for anyone who has suffered from disordered eating in the past. But for someone without a history of disordered eating, there’s really no harm in doing a juice fast or any fast for one or two days, as long as the person is hydrating appropriately. Beyond a few days, there’s no way one can really meet his/her micro and macronutrient needs for vitamins, minerals, fat, fiber, and protein through a fast (including a juice fast). So, if the fast is prolonged, say for two weeks, he/she will start to break down muscle tissue, resulting in a weight loss (muscle tissue is heavy and dense, about 1.7 or 2 times the weight of fat mass). This can’t be sustained without becoming malnourished, nor is it ideal to waste muscle tissue and lose strength. In such a state a person can expect to be in ketosis, a state characterized by elevated levels of ketones in one’s urine or a fruity or acetone-like smell in one’s breath. Ketosis is one of the hallmarks of starvation/malnutrition.
Kayla: I know detoxification is a trendy concept. What are the toxins people are trying to rid from their bodies?
Megan: Usually the claims about detoxification on these products are overstated and generalized/non-specific. Most refer to PCBs, lead, heavy metals, or environmental toxins like food additives, food coloring, pesticide residue, etc.
Kayla: And would a cleanse rid the body of these toxins?
Megan: Actually, there’s no evidence that a cleanse or fast would (although, as long as one is fasting, one is likely taking in less of these compounds, though they’re reintroduced once the fast ends). There seems to be nothing about a cleanse that is as beneficial as adopting a good quality of diet consisting primarily of plants and whole foods. But there isn’t much research out there; there haven’t been many high quality studies on cleanses because higher preliminary studies show no benefit. Cleanses are typically promoted by testimonials given by celebrities or people who have no training/educational background (major red flag).
One problem with cleanses/detox diets is that if someone had a poor diet before doing on a cleanse, they usually revert back to that diet afterward, as they often don’t build skills to enable sustainable changes. So, unless he/she makes a concerted effort to change diet and lifestyle, he/she will return to feeling just as poorly as prior to the cleanse.
Kayla: …because he/she is just reintroducing all the old stuff…?
Megan: Right. The benefits are not sustained and not sustainable. So if you wish to feel better, or are seeking the reported benefits of something like a cleanse or detox diet, the best bet is really working on changing quality of diet and increasing activity, both of which sustainably promote feelings of well being (without undesirable side effects).
And it’s most important to note that not everyone reports feeling better during or after a cleanse. Most people report feeling disorientated or lethargic, dizzy, weak, a little confused or groggy because they’re malnourished and not getting enough glucose to the brain to fuel proper cognitive processes and physical functioning. Some people often report feeling lighter, and I can see that because one may lose weight in the form of fluid and stool bulk primarily (and perhaps a smaller proportion of fat mass and muscle mass depending on how the cleanse or fast lasts). But most often, participants complain of weakness, confusion, or just feeling “out of it.”
Kayla: Then why do people believe a cleanse is beneficial?
Megan: In part due to the power of testimonials—some people do report feeling better. Certainly people can report feeling better after adhering to a really nutrient-dense juice cleanse for several days in a row. But when someone is coming from a place where their diet is poor, of course they are going to feel better when diet improves. The problem is that it’s short term. We know that fad diets don’t work in terms of sustaining weight loss, and cleanses/detox diets are not exceptions.
Some people notice that a one or two-day cleanse or fast helps them to break habits of mindless eating and get back to a cleaner quality of diet. For example, someone who takes a one or two-day fast or cleanse after the holidays. Having said that, if you’re someone who is willing to stick to a juice fast or cleanse for just a few days as a means of hitting a ‘reset’ button, then you’re probably also apt to resume your pre-holiday eating style without doing the cleanse/fast.
Kayla: I know fasting can be dangerous because of the risk of malnourishment. Are there other risks? Can a cleanse regimen be dangerous?
Megan: Cleansing and fasting can be especially difficult and contraindicated for people with altered nutrient needs due to illness (diabetes, kidney disease, etc.). So, prior to participating in a cleanse or fast, I’d suggest consulting first with your physician.
Kayla: Earlier, you mentioned colon cleansing. Will you explain what a colon cleanse is? Why do people do it, and what are the pros and cons?
Megan: A colon cleanse is usually performed with an enema, commonly salt water or purified water injected into the colon. The idea is to remove any metabolic waste that the colon hasn’t removed on its own. Conventional physicians usually don’t support colon cleanses because there isn’t evidence to support the reported benefits. The colon is self-cleaning… it does a really good job of getting rid of metabolic waste on its own. So, we don’t need a procedure to cleanse the colon. In fact, introducing a foreign object into the colon can actually be pretty risky. Perforation of the bowel is another big risk with colon cleansing, as are infections and electrolyte disturbances.
Proponents of the colon cleanse will say they are introducing higher levels of good bacteria and getting rid of “bad” bacteria in the intestines, but there is really no evidence of that being the case, and the introduction of good bacteria is something you can get from eating probiotic-containing foods and a primarily whole-food plant based diet.
Also, we have a liver and other important organs that perform that function for us without prompting. Environmental toxins can not be metabolized or cleared by a cleanse or fast, unfortunately. If you are looking to make a change to feel better, my advice is to follow something that is sustainable for you, preferably a nutrient-dense, plant-based diet—though not necessarily vegetarian—with a high intake of whole foods: fruits, vegetables, whole grains, legumes and plant based fats.
What are your experiences with cleanses and fasts? Have they been helpful or triggering of disordered eating thoughts and behaviors?
And thanks so much for your interest in this Q&A series. Please keep us posted on future topics you would like us to cover in future Q&A posts. Thanks for reading!
In good health – Megan and Kayla