Detox diets - do they work?

"I need to detox!" It's a common refrain at this time of year.

But are detox diet plans all they're cracked up to be? 

Dietitian Elizabeth Stewart* gets to the bottom of this fashionable trend. Reproduce with kind permission from the January 06 issue of Australian Healthy Food Guide. See

The festive season is well under way - by the end of it we will have all eaten (and drunk!) well with friends and family, been on holiday, relaxed and generally enjoyed ourselves.

Back to work and/or our usual routines and everyone seems to be talking about the need to lose weight or "tone up" after the excesses or indulgences of the past few months. Magazines have already started offering tips on how the rich and famous get their unachievable bodies, with often bizarre diets and exercise regimens, and we become tempted to try them. After all, what harm can they do?

One that appears frequently, and in many forms, is the so-called "detox" diet. What is it? Key in the words "detox diets" into a search engine on the internet and up come 1,600,000 references in just 29 seconds!

The claims

What all of the websites seem to agree on is the main idea behind the detoxification diet: we need to periodically clear the "toxic waste" from our bodies in order to stay healthy because of exposure to environmental hazards like cigarette smoke, air pollution and pesticides, and toxins from poor diets. These toxins are said to build up in our system and the health problems they cause include weight gain, bloating, headaches, dull skin, cellulite, fatigue, aches and pains, and a general lack of wellbeing. A toxin is usually defined as a chemical or poison that is known to have harmful effects on the body.

The general claims made in relation to detox diets include rapid weight loss; improved digestion; improved hair, nails and skin; improved energy levels; a boosted immune system; and the banishment of cellulite. Testimonials on many of the websites appear to endorse these health gains following a detox diet.

What is involved

Most detox diets recommend you go on the diet for a period of between one day (for a quick fix) and one month. Most involve fasting for short periods of time; consuming only fruit and vegetables; cutting out wheat and dairy products; consuming only a limited range of foods; and avoiding caffeine and alcohol.

Although the types of foods allowed vary widely among the different detox diets, most include fruit, vegetables, beans, nuts, seeds, herbal teas and large amounts of water. Wheat and dairy products, meat, fish, eggs, caffeine, alcohol, salt, sugar and processed foods are usually banned.

Vitamin and mineral supplements are often recommended as an adjunct to detox diets, along with herbal supplements to help the "purification" process. Milk thistle is one of the most popular herbal supplements, which contains a compound called silymarin, believed to enhance liver regeneration and promote its detoxification function. Clinical trials have been inconclusive, but the extract is well tolerated by the body and the antioxidant properties may be beneficial, although not in a "detox" sense.

Flaxseeds and psyllium husks are also frequently recommended. Constipation is one of the effects of spending a period of time on a detox programme, so the addition of any type of fibre into the diet is important, and both of these foods do have a laxative effect.

Most forms of detox diet involve some type of fast, with only liquids allowed during that time, which is followed by the gradual introduction of certain foods. You are encouraged to chew your food thoroughly, drink very little while eating and relax prior to each meal.

Do we need to detox?

So is the basic premise that we need to periodically clear the toxins from our body supported by science?

The short answer is: No. Our bodies constantly filter out, break down and excrete toxins and waste products. These can include alcohol, medications, products of metabolism and digestion, dead cells, and chemicals from pollution and bacteria. This is performed by our body's in-built "detoxifiers" - the liver, kidneys, skin, lungs, intestines and immune system. All these toxins are excreted by the body within hours of being consumed, in the form of faeces, urine and perspiration. There is no scientific evidence that a detox diet helps rid the body of toxins any faster, or that the elimination of toxins will make you a healthier, more energetic person.

In fact, a detox diet that encourages the increased excretion of faeces and urine can result in potentially serious health problems. It can cause the depletion of essential minerals such as calcium, phosphorous, sodium and potassium, which leads to dehydration and altered electrolyte levels. Electrolytes are needed for metabolism.

What about the other claims?

WEIGHT LOSS. Yes, you may well lose weight on a detox diet. Fasting or severely restricting what you eat limits the intake of energy or kilojoules, and rapid weight loss can occur, depending on the length of time the fast lasts. This weight loss is largely water and glycogen (the body's carbohydrate store) rather than fat, which means that the weight is rapidly regained once the detox diet is completed. Lengthy fasting may in fact slow metabolic rates and the breakdown of fat stores, and result in loss of muscle. What concerns health professionals is that this rapid weight loss, followed by equally rapid weight gain after the diet is stopped, often leads to yo-yo dieting - one failed diet followed by another. The body's response to this is to prevent any weight loss in case it needs its stored fat and glycogen to survive a lengthy fast or lack of food.

REDUCED HEADACHES. Yes, this does happen - probably because of the elimination of caffeine and alcohol. Most people will benefit from a reduction of both caffeine and alcohol in their diet, but beware of sudden total withdrawal of both. The four or five days of violent headaches may make you so miserable that you head back to the coffee pot.

LESS BLOATING. Yes, but that's probably because you are eating a lot less food!

CLEARER SKIN. This is possible. It's most likely to be from the improved hydration.

DECREASED CELLULITE. The term "cellulite" was coined in 1973 to refer to the dimpled appearance of the skin that some people have on their hips, thighs and buttocks. This appearance is much more common in women than in men because of differences in the way fat, muscle and connective tissue are distributed in men and women's skin. Will a detox diet decrease the cellulite? It's doubtful, although a loss of weight (as with any diet), and therefore body fat, may see the fat deposits decreased, which would mean there would be less of the dimpling effect on the skin.

FEEL BETTER AND HEALTHIER. Yes, you may feel better, but it's debatable whether this is a result of the detox diet or a result of the loss of weight and the euphoria of doing "something good" for your body.

Certainly any low-fat, high-fibre diet is going to be better for you than a diet high in fatty, processed food.

Are there any pros for detox diets?

PROS: Many of the detox diets on the web and in magazines do encourage good dietary habits such as eating more fruit and vegetables, drinking more water, and cutting back on caffeine, alcohol, high-sugar and high-fat foods. Any diet which encourages people to be aware of what they are eating, and to cut down on junk food and processed foods, is all for the good.

CONS: The main problem with detox diets is that they can lead to a diet which is very short of essential nutrients. Any weight you may lose is temporary, due to a loss of water and severe kilojoule restriction. This can be pretty demoralising when the weight is rapidly put back on. Some people also experience side effects like headaches, fatigue and nausea, which advocates say is the result of the body detoxifying, when in reality it's caused by the lack of food. This lack of food also makes it nigh-on impossible to adhere to the diet for long periods of time.

There is also the risk that strict detox plans can contribute to an unhealthy obsession with food and even the development of an eating disorder.

Should you avoid these diets?

YES.  Detox diets are very unwise for people who are undergoing growth and development such as children and adolescents, pregnant or breastfeeding women, older adults who have impaired renal or hepatic function, those with diabetes or heart disease, and people with irritable or functional bowel disease.

The body's own detox system

  • Breaks down fats, proteins and carbohydrates - it recycles what it can back into the body and the rest goes to the kidneys.
  • Controls the levels of chemicals in the body and eliminates excess hormones and helps to maintain electrolyte and water balance.
  • Filters the blood to remove chemicals and bacteria.
  • Helps to balance the body's internal environment by removing excess water, gases, salts and other organic
  • Removes wastes from the body in the form of urine.
  • Regulates the composition of blood and blood pressure.
  • During perspiration toxins are released through the skin.
  • Transforms toxins from lipid-soluble or oil-based compounds into water-soluble forms, which can then be removed by the kidneys. The liver and lungs also carry out this process.
  • The tissue lining the lungs acts as a barrier against toxins entering the body through the air.
  • Releases antioxidant enzymes to counteract free radicals from the environment.
  • Antibodies patrol the respiratory tract, defending it from microbes and tumour cells.
  • Exhales out carbon dioxide waste from air.
  • Friendly bacteria live in the large intestine and they play a huge role in the detoxification of the body when waste material passes through by degrading toxins and
    preventing colonisation by pathogens.
  • Indigestible waste products pass through the intestine and are released as faeces from the body.
  • When you receive a cut, all sorts of bacteria and viruses enter your body through the break in the skin. Your immune system responds and produces macrophages to clean the
    area. Inflammation and pus are both side effects of the immune system functioning properly.
  • Lymph fluid and lymph nodes produce white blood cells or lymphocytes. The lymph nodes swell with lymphocytes
    which trap invading disease microorganisms in the node.

The bottom line:

There is no good evidence that a detox diet is necessary or that it actually works.

The last word can be left to the British Dietetic Association:

"Detox diets are marketing myths rather than nutritional reality. They sound like a great concept and it would be fabulous if they really delivered all that they promised! Unfortunately many of the claims made by detox diet promoters are exaggerated. While they may encourage you to eat more fruit and vegetables, it's best to enjoy a healthy, varied diet".

Ultimately, if, after all this, you still want to follow a detox diet, look for one that has the fewest restrictions and only use it to kick-start a longer term, more varied healthy eating plan.

*Elizabeth Stewart is from Massey University, New Zealand