Online exclusive
As well as Jennifer Bowden’s columns in the NZ Listener and here at listener.co.nz, subscribers can access her fortnightly “Myth busters” column in which she explores food and nutrition myths. This week she looks at the science - or rather lack of - behind detox diets.
With promises of rapid weight loss and the elimination of toxins, detox diets are seen as an appealing reset in the lead-up to summer.
Whether it’s fasting, juicing or supplement-based plans, detoxes claim to promote health and wellbeing through a fresh start. But are they really beneficial for your health or simply another fad?
Before jumping on the detox bandwagon, let’s separate fact from fiction by looking at the scientific evidence to see what, if any, risks they pose to your health.
The concept of detoxifying the body dates back thousands of years to Greek, Roman, Indian and Native American cultures, where fasting, saunas, herbs, rebounding, dry brushing, water, rest, exercise and meditation were used. These interventions targeted toxin elimination and health improvement.
However, given our Western obsession with being thin by any means possible (irrespective of the potential harm), detoxing is often now used as a kickstart for weight-loss efforts.
Modern detox diets often involve juice fasts, calorie restriction or dietary changes and typically include supplements of vitamins, minerals, diuretics, laxatives or “cleansing” foods. For example, the liver cleansing diet is an eight-week, plant-based, dairy-free plan that allows only unprocessed foods, along with Epsom salt and liver tonics. The lemon detox diet replaces all solid food for eight days with a mix of purified water, lemon juice, tree syrup and cayenne pepper, along with herbal laxatives and sea salt water. These types of detox diets are far from nutritionally balanced.
Despite their popularity, there is little scientific evidence to support their long-term effectiveness. A scientific review published in 2015 in the Journal of Human Nutrition and Dietetics found exactly zero randomised controlled trials on the effectiveness of detox diets.
Some researchers have conducted studies on detox diets that claim to show positive results. However, these studies were poorly conducted with small participant numbers, no control group for comparison and often relied on participants’ self-reporting results rather than objective clinical measures such as blood tests.
Detox diets significantly restrict the calories consumed by dieters by limiting the quantity and variety of foods. This causes issues, as noted in a 2022 review in Frontiers in Nutrition. Firstly, fasting increases cortisol levels in young, healthy women; an intake of 1200 kcal/day increases stress hormone levels in women. And that increased stress may stimulate the appetite. In other words, detox diets may induce bodily stress, raise cortisol levels and increase appetite, leading to rebound binge eating after (or even during) the detox.
What’s more, commercial detox diets often induce nutrient deficiencies and expose dieters to harmful ingredients. America’s FDA has charged several companies for selling detox/cleansing products that contain dangerous ingredients.
In 2019, for example, the FDA advised consumers not to buy Dr Forster’s Detox Plus, which contained tadalafil, paynantheine and mitragynine. Tadalafil is the active ingredient in erectile dysfunction medication Cialis, while paynantheine and mitragynine are components of the Mitragyna speciosa plant, commonly known as kratom, which is native to Asia. Kratom stimulates the same opioid brain receptors as morphine and may have properties that will expose users to the risks of addiction, abuse and dependence.
The reality is that 99% of humans have a perfectly functioning liver and two kidneys which do a fine job of removing external and internal toxins from the body. Plus, we excrete toxins through sebum and sweat.
While detox diets may seem like a quick, harmless addition to your health regime, the scientific evidence suggests otherwise. These restrictive programmes can lead to binge eating, heightened stress, nutrient deficiencies and even harmful side effects from unregulated products. Focus instead on a balanced, whole-foods diet rich in fruits, vegetables, whole grains and lean proteins. Your body is already equipped with an efficient detox system and nourishing it with wholesome foods is a much safer and more sustainable way to preserve your long-term health.
