The truth about detox diets: Science vs. myth

Guest article from our nutrition expert Dr. Dorothea Portius

The first warm rays of sunshine tickle the skin, the birds are chirping, and everywhere is starting to bloom – spring is here! Now is the perfect time for a fresh start. Just as we polish our homes, declutter the basement, and chase away the winter dust, many also want to give their bodies a refreshing treatment. Detox diets promise just that: to "cleanse" the body, free it from toxins, and provide it with new energy. But does it really work? Does our body even need a special detox treatment, or is that just a clever marketing trick? 

Is there a scientific definition of "detox diets"?

The term "detox" is not clearly defined in medicine.While "detoxification" in clinical medicine describes the treatment of drug or alcohol addiction, the term is often used nonspecifically in the wellness and nutrition sector. Many detox programs claim that they eliminate environmental toxins, heavy metals, or metabolic waste from the body – usually without clearly stating which substances are involved and through which mechanisms they are to be eliminated. There is also often a lack of clinical evidence for most detox promises.

Detoxification - a physiological body process

Our body has highly developed, natural detoxification systems that work around the clock.The most important organs for detoxification are:

• Liver: Converts fat-soluble toxins into water-soluble substances so that they can be excreted through urine or bile.
• Kidneys: Filter water-soluble breakdown products from the blood and excrete them with urine.
• Intestine: Through fiber and commensal gut bacteria of our microbiome, toxins are bound and eliminated through stool.
• Lungs: Remove volatile substances such as carbon dioxide.
• Skin: Small amounts of heavy metals and other substances can be excreted through sweat.

The body's own detoxification occurs in two main phases:

1. Phase I reactions: Enzymes (e.g., cytochrome P450 system) chemically alter toxic substances so that they can be further processed.
2. Phase II reactions: These substances are coupled with other molecules (e.g., glutathione, sulfates, or amino acids) to make them water-soluble and excretable.

Detox diets in fact check: hype or real help?

Despite the popularity of detox diets, there is hardly any scientific evidence for their effectiveness. There are only a few studies that demonstrate that commercial detox diets actually lead to increased detoxification.

1.Excretion of environmental toxins

Some studies suggest that certain foods like coriander, chlorella, or citrus pectins may have a detoxifying effect. However, these effects have mainly been observed in animal studies, not in clinical human studies.

2. Detoxification through fasting?

Many detox programs involve significantly reduced calorie intake, fasting programs, or the elimination of certain food groups, which can promote nutrient deficiencies. This can paradoxically hinder the body's own detoxification, as important micronutrients for phase II detoxification are lacking (e.g. Vitamin B12, folic acid and certain amino acids). Additionally, when body fat is broken down, stored toxins can enter the bloodstream and temporarily increase the burden on the body.

3.Detox diets and weight loss

Many turn to detox programs in the hope of losing weight quickly. In fact, there can be a visible decrease in the short term – but this effect is usually based on the loss of water and stored carbohydrates, not body fat. Since carbohydrates bind water in the form of glycogen, their withdrawal initially leads to dehydration of the body. However, as soon as normal eating is resumed, the stores fill up again, and the weight increases again.

In the long term, restrictive detox diets can even be problematic: They can promote cravings and often lead to later weight gain. Therefore, sustainable weight loss is better achieved with a balanced, nutrient-rich diet than with short-term detox programs.

Risks of Detox Diets

• Nutrient Deficiencies: Lack of proteins, vitamins, and minerals can disrupt metabolic processes.
• Electrolyte Imbalances: Excessive water intake or the use of laxatives can lead to sodium or potassium imbalances.
• Muscle Loss: Very low calorie intake first leads to the breakdown of muscle mass.
• Increased Toxic Exposure: During the breakdown of fat tissue, stored environmental toxins can enter the bloodstream.

How can you support natural detoxification?

Instead of relying on questionable detox cures, a healthy diet and a sustainable lifestyle can optimally support the body's natural detoxification mechanisms:

1. Drink plenty of water

• The kidneys filter about 200 liters of fluid daily, of which about 1.5–2 liters are excreted as urine.
• Inadequate fluid intake can impair kidney function and slow down the excretion of toxins.
• Recommended: Drink at least 1.5 to 2 liters of water per day – more if exercising or in heat.
• Tip: Herbal teas and diluted lemon or ginger water additionally support hydration.

2. Dietary fiber for healthy digestion

• Dietary fibers bind toxins in the intestines and promote their excretion through stool.
• A fiber-rich diet also supports the gut flora, which plays an important role in detoxification.
• Recommended: Daily 30–40 g of fiber from whole grain products, vegetables, legumes, nuts, and seeds.
• Tip: Start the day with a portion of oatmeal with flaxseeds and enrich your salad with some chickpeas for lunch.

3. Sufficient proteins to support the detoxification process

Proteins play a central role in the body's own detoxification process.Certain protein building blocks (amino acids) are particularly sulfur-containing amino acids such as methionine and cysteine, which are essential for the synthesis of glutathione, one of the body's most important antioxidants and detoxification factors. They also play a role in proteostasis - a molecular marker of aging.

What is crucial is not only the quantity but also the quality of the proteins consumed. High biological value proteins contain all essential amino acids in optimal ratios and thus promote efficient detoxification.

• High-quality protein sources:
  • Animal: Eggs, fish, lean meat (e.g., chicken, beef fillet), dairy products (z.Be.g., low-fat quark, feta).
  • Plant-based: Quinoa, soy products (e.g.Tofu, tempeh), lupin, as well as combinations of grains and legumes (e.g. beans with rice, chickpeas with sesame (hummus)) to ensure a complete amino acid supply.
• Recommended intake: Depending on activity level, a daily protein intake of 0.8–1.2 g per kg of body weight is recommended. Athletes or individuals with increased metabolic stress may have a higher requirement.

Tip: Make sure that each dish contains a high-quality protein source. Add some nuts and yogurt to your oatmeal breakfast or complement the salad with chickpeas and whole grain bread and hummus, feta, or chicken strips.

4.Antioxidant-rich foods to support liver function

• Antioxidants are essential to neutralize free radicals that occur during detoxification.
• Important antioxidants include Vitamin C, Vitamin E, Selenium, and secondary plant compounds (z.Bphenolic acids, glucosinolates, carotenoids).
• Recommended: Plenty of colorful fruits and vegetables (berries, bell peppers, spinach), as well as herbs like turmeric and ginger.
• Tip: Your plate should never look colorless; half should be filled with seasonal and preferably regional fruits and vegetables. How about apples and berries in porridge or carrots, tomatoes, or radishes in salad?

5.Movement gets the metabolism going

• Exercise improves circulation and supports liver detoxification and kidneys in filtering toxins.
• Through sweating, small amounts of heavy metals like arsenic and cadmium are excreted.
• Recommended: At least 150 minutes of moderate exercise per week (e.g., walking, cycling, yoga) and/or 75 minutes of intense training (e.g., jogging, strength training).
• Tip: No time for sports? How about walking a few stops instead of taking the bus or train?

6. Avoid heavy metal exposure

• Heavy metals like mercury and lead can accumulate in the body and overload the detoxification systems.
• Plastic packaging often contains plasticizers such as Bisphenol A (BPA), which can have hormonal effects.
• Recommended:
  • Choose fish with low mercury levels (e.g., salmon, trout, herring instead of tuna).
  • Use glass instead of plastic for food storage.
  • Prefer organic foods to minimize pesticide residues.
• Tip: Prefer unwrapped fruits and vegetables in the supermarket. This not only reduces plastic waste but also allows you to buy exactly the amount you actually need – thus avoiding food waste.

Conclusion - Detox Diets

Detox diets are not scientifically substantiated and are often more marketing than medicine. The body has effective mechanisms for detoxification that can be optimally supported by a healthy diet and lifestyle. Those who want to stay healthy in the long term should focus on sustainable dietary strategies – and not on short-term detox trends.