We are constantly bombarded by the media with the next miracle diet. One that crops up time and time again, especially in January following the excesses of the Christmas season is a detox diet. As fitness and nutrition consultants we’re constantly asked our opinions on these so called wonder solutions. So what’s the deal and do they work?

Detox diets claim to be a way to rid our body of toxins that build up over time, from our consumption of various food and drinks (preservatives, pesticides, etc) and from external environmental factors. They promise to deliver instant weight loss and feelings of wellbeing.
It all sounds too good to be true. The fact is, it probably is.

The theory

Advocates of the detox programme claim it aids the body's natural cleansing process
Hillcliff logo | Hillcliff Personal Training North London - Barnet  Fasting ‘rests’ the organs
Hillcliff logo | Hillcliff Personal Training North London - Barnet It ‘stimulates the liver’ to drive out toxins from the body
Hillcliff logo | Hillcliff Personal Training North London - Barnet It promotes elimination of toxins through the intestine, kidneys and skin

What does a detox diet involve?

There are many variations, lasting from a few days to a few months. The protocols range from fasting, to highly restricted diets, to juicing and the more extreme measures of colonic irrigation and bowel enemas. Herbal supplements are often incorporated into a detox programme. 


Scientists and nutritionists report a number of issues with these diets both in the short and longer term. 

Hillcliff logo | Hillcliff Personal Training North London - Barnet  Cutting out major food groups  - this will restrict the necessary nutrients your body needs to function effectively. One example is protein which can be especially problematic. We need protein in our diets for the maintenance and growth of every cell in the human body. The essential amino acids in protein are necessary for mood regulation and a deficiency can cause irritability and depression. Over long periods it can also cause anaemia, hair loss, liver damage and reduce immunity. Couple this with the high percentage of carbohydrate intake necessary when you cut out protein (as with a juicing diet), and insulin levels cause a big surge of energy followed by the inevitable crash.

Hillcliff logo | Hillcliff Personal Training North London - Barnet  Headaches, dizziness, nausea - associated with dehydration and a highly restricted calorie intake.

Hillcliff logo | Hillcliff Personal Training North London - Barnet  Fluid loss - although initial weight loss is often achieved on a detox programme in these strict regimes, the majority is fluid loss, often as a consequence of frequent trips to the toilet.

Hillcliff logo | Hillcliff Personal Training North London - Barnet  Lean tissue loss - with a restrictive calorie intake the body will use both fat and lean muscle tissue as fuel to maintain it's main functions.

Hillcliff logo | Hillcliff Personal Training North London - Barnet  Digestive imbalance - because these diets rely predominately on carbohydrates they can overwork the intestine. Diarrhoea is a common result. Add to this the fact that some of the diets promote the use of laxatives and you will deplete electrolytes, rid your body of the ‘good’ bacteria within your stomach and consequently impair bowel function. All these factors dispel the myth that the diets actually give the gut and intestinal tract a ‘rest’. Indeed there are reports that continued use of such plans can lead to metabolic acidosis, resulting in excessive acidity in the blood.

Hillcliff logo | Hillcliff Personal Training North London - Barnet  Metabolic slow down - severe calorie restriction and fasting puts your body into ‘famine mode’. It tries to hold onto any fat stores it can and slows the metabolism down to preserve energy stores. Once you start to eat again the weight will go back on - often more than you lost in the first place - as you no longer utilise your energy sources at the same rate you used to.


It’s not all bad news. There are some plus points - the simple one being that these diets encourage a number of good eating habits; increasing your intake of fruit and vegetables, drinking more water, reducing the amount of saturated fats, processed foods and caffeine and alcohol we consume. They encourage people to be more mindful of what they are eating. However, we would argue that all this can be achieved by following a healthy, balanced diet without the need for these extreme and potentially harmful measures.

Scientific evidence

Scientists and health experts have been sounding the alarm bells over recent years, questioning the so-called scientific evidence that claim these detox regimes actually work. The fact of the matter is your body does an incredible job of ridding itself of anything harmful. Within an hour of eating we begin to neutralise and remove anything ‘toxic’. There is no basis of fact to support the claims that a detox diet is in any way necessary for healthy living.

How the body cleanses itself

*  Respiratory system – before any harmful substances even attempt to enter your system your nasal passages trap and filter them out. Of course sometimes they manage to infiltrate beyond the nose. Your lungs are ready and waiting with phagocyte cells which are there to defend your respiratory tract by attacking and destroying anything harmful.

*  Kidneys
 – the kidneys clean and filter your blood and dispose of toxins in your urine. Dehydration adversely affects the kidneys performance so it’s vital to make sure you drink plenty of water.

*  Liver
 – the liver is amazing. As the principle detoxing organ it is constantly processing and eliminating any potentially harmful substances.

*  Small intestine - lined with villi and microvilli that aid the absorption of nutrients into the bloodstream, these tiny cells stop any toxins from entering the blood through the small intestine.

*  Large intestine/colon – this eliminates waste material and like the lungs and small intestine is lined with cells whose role is to prevent harmful elements from being absorbed into the bloodstream. This is why it’s so important to ensure you each plenty of fibre and wholegrains.

*  Lymphatic system – Lymphocytes are a form of white blood cells that trap and destroy harmful substances during the process of filtering excess fluid throughout the body via the lymphatic system. This detoxified fluid is then returned to the bloodstream.

*  Skin – sweating releases toxins from the body. Another great reason to exercise.

How amazing is all of that?? It’s incredible. Of course that doesn’t mean that you can abuse your body and expect it to carry on working efficiently. As mentioned, hydration and fibre are extremely important and likewise saturated fats, processed foods, alcohol, caffeine etc all hinder the function of each and every one of these processes.

Summary – eat well and exercise

Bottom line; your body does a fantastic job of 'detoxifying' without the need for an expensive diet, supplements or extreme measures. If you are looking for a long term solution there is no substitute for regular exercise, a good nights sleep and a healthy balanced diet, rich in nutrients, vitamins and minerals.

Cutting down on saturated fats, salt, sugars and processed foods as a lifestyle change is the key to long term success for all the benefits a so called wonder detox diet promises; weight loss, increased energy, improvements in skin and circulation.

Not one of these diets can come close to the detox systems we already have in our bodies. If you'd like more information on maintaining a healthy balanced diet check out our nutrition packages and get in touch.

Hillcliffdo detox diets work