Detox Diets - Science or Science Fiction?

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Detox diets, a favourite spruik of wellness influencers, are often touted as an easy weight loss option. But what are detox diets and do they really work? Let’s see what science tells us.

Types of detox diets

Detox diets (or cleanses) loosely fall into three categories: 1) those that replace solid food with liquids, 2) those that supply nutrients to “boost” your liver and kidney function to improve removal of toxic substances, and 3) those that cleanse your digestive system (think colon cleanse).

Why “detox”?

Detox diets are dietary interventions with the purpose of losing weight and “cleansing” your body of unspecified “toxins” – a result of our environment and lifestyle habits (pollution, alcohol, caffeine, refined foods, and additives to name a few) or so we are told. Other supposed benefits of these diets are more energy, glowing skin, improved health, and better digestive functioning.

The detox diet process

Most detox diets operate through some form of restrictive eating combined with fasting, while others require you to purchase various supplements, shakes or herbal teas. The types of foods allowed and banned also vary greatly between different detox diets. Commonly though, foods such as wheat, dairy, meat, ultra-processed foods, caffeine and alcohol will be banned while fruits, vegetables and water are generally permitted.

Does weight loss occur?

Rapid weight loss can occur on a detox diet but due to the nature of the weight loss, it is unlikely that people will maintain this and will instead find that the weight is regained as rapidly as it was lost. This is due to the type of weight loss that occurs on these restrictive diets. Foods that contain carbohydrate (e.g. bread, pasta, rice, cereals) are restricted on detox diets. Carbohydrates are broken down by the body into glucose, the preferred energy source of the body. When there is no or low carbohydrate intake through diet, the body turns to its own glucose stores in the liver and muscle, where it is stored as glycogen. To release the glycogen, water is also needed so the initial weight loss seen on detox diets is mostly due to lost water, not body fat. This weight will be put back on again after the person returns to their normal diet, following the detox.

Do people really feel better on a detox diet?

Anecdotally, people often claim to feel better following a detox diet, however, this can be explained in part by the fact that people cut down on nutrient-poor, calorie-dense ultra-processed foods and alcohol for a few days, while simultaneously increasing vegetable and water intake.

Is a detox diet necessary?

Scientifically, there is little evidence that detox diets actually remove toxins from the body. Our own body systems including the gastrointestinal tract, lungs, kidneys, liver and immune system, are very efficient at removing waste products and there is no evidence to show that detox diets can remove waste products any faster than our own body systems can do it.

Seek medical advice

If you have your heart set on doing a detox diet, always seek medical advice. Side effects from detox diets can include fatigue, dizziness, headaches, gastrointestinal upset and dehydration. Long-term restrictive eating can also result in vitamin and mineral deficiencies. For people with particular health conditions (like diabetes) there can be serious medical consequences as a result of restrictive eating and fasting. Children, and pregnant and breastfeeding women should avoid detox diets due to their specific nutrient requirements for health and growth.

The verdict

There is little harm likely to come to a healthy person undertaking a detox diet over 2-3 days, however, you may find your wallet permanently thinner, rather than your waistline. While a detox diet might be a kickstart for healthier habits, long-term health will only come through modifying lifestyle behaviours – drink more water, eat more fruits, vegetables and wholegrains, eat less ultra-processed foods, drink less alcohol and incorporate exercise into your day.

If you are concerned about your diet or need help making long-lasting dietary changes, please consider seeing an Accredited Practising Dietitian.

CHEW happily!


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