Updated 20 October 2015

Do we really need ‘five-a-day for health’?

British health guru Zoë Harcombe, debunks the notion that we need a fixed or minimum amount of fruit and vegetables – the famous five-a-day – to stay healthy.

As a species we have always been obsessed with our health, and throughout the millennia we have focused on a multitude of ways to achieve and maintain optimal health. 

Food as medicine

There has never been a shortage of superstition and strange “home remedies”, but by and large we appreciated the importance of factors like enough fresh air, exercise and especially a healthy diet. In fact, more than 400 years BCE the Greek physician Hippocrates said: “Let thy food be thy medicine and thy medicine be thy food.”

Food and fresh air are self-explanatory, but the issue of what we should eat and what constitutes the optimal diet is a lot more complicated. The human diet is extremely varied, with people like the Eskimos who exist almost exclusively on meat on the one end of the scale, to vegans who shun all animal products on the other.

There are currently more obese than starving people on planet earth, but on the evolutionary scale this is a very new development, and for most of our history finding enough food to eat was a daily struggle.

This meant that people couldn’t afford to be choosy and ate what they could find – and that very few people were overweight. In some cultures being fat is still a sign of wealth and status.

Read: Is the Zoe Harcombe diet the answer to yo-yo dieting and disease?

Opinions differ on when exactly so many of us started getting so fat, but before the 1950s there were certainly far fewer obese people than nowadays. Okay, in those days people got more exercise, portions were smaller and fast food was in its infancy, but there was something else . . .

Ancel Keys and saturated fat  

Ancel Keys was an American scientist who studied the effects of diet, and in particular the effects of different kinds of dietary fat, on human health.

In the 1950s Dr Keys forcefully and very persuasively championed the notion that saturated fats raise cholesterol and thereby cause heart disease. His theory was well received because at that stage heart disease had become the biggest killer in the US and people wanted answers. (It is interesting to note that margarine became popular during World War II and that the prohibition on colouring margarine yellow was lifted in the 1950s, making it even more popular.) 

In 1956 the American Heart Association announced that eating large amounts of butter, lard, eggs and beef would lead to coronary heart disease. This led to recommendations by the US government that people should adopt a low-fat diet to prevent heart disease.

Read: Saturated fat may not cause heart disease after all

Dr Keys’ theory subsequently became widely accepted and formed the basis of the recommended Western diet for more than forty years. Based on the good doctor’s recommendations, we cut back on saturated fat and increased our intake of carbohydrate and polyunsaturated fats, which in practical terms meant that instead of eggs, meat and cheese we started eating grains, pasta, starchy vegetables and fruit.

Tied to increasing our carbohydrate intake is the popular campaign of five-a-day in countries like the USA, the UK and Germany which encourages the consumption of at least five portions of fruit and vegetables per day.

This was initiated by the World Health Organisation which recommended that individuals consume at least 400g of fruit and vegetables per day. 

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Image: Who is right? These controversial juxtaposed photos appeared on the internet, comparing Nigella Lawson to Gillian McKeith. They are the same age, but Nigella smokes, drinks, eats meat, butter and desserts while "health guru" Gillian recommends a vegetarian diet, rich in fruits and organic vegetables.

It doesn’t work!

The trouble with this new way of eating was that it didn’t work. During the low-fat high-carb decades we got (a lot) fatter and heart disease only got worse.

ReadActor Damon Gameau says low-fat diet made him fat

During these years there was the odd voice in the wilderness that refused to jump on the low-fat bandwagon. People like Dr Robert C. Atkins (the Atkins Diet) refused to believe that carbs were the answer and created a very successful low-carbohydrate eating plan in 1972. 

The idea of a low-carb, high-fat diet was recently popularised in South Africa by Prof Tim Noakes with his book The Real Meal Revolution. The book is based on his interpretation of “Banting”. (William Banting lived in England in the nineteenth century and popularised a weight loss diet based on limiting refined carbohydrates.)

Read: Tim Noakes on carbohydrates

In February 2015 Prof Noakes and Karen Thomson, founder of The Sugar Free Revolution Online Programme, hosted The Old Mutual Health Convention with internationally acclaimed doctors and researchers in Cape Town.

One of the speakers at the convention was well-known author Zoë Harcombe. What triggered Zoë’s research into nutrition was trying to understand why obesity increased almost tenfold in the UK between 1972 and the end of the twentieth century. Her conclusion was that "the dietary advice that we are getting changed. We started moving away from fats and increased our carbohydrate consumption, which lead to huge increases in obesity and type 2 diabetes."  

Zoë Harcombe on five-a-day

On March 11, 2012 Zoë Harcombe published an article Five a day: The truth on her website in which she debunks the notion that we need a certain amount of fruit and vegetables a day to stay healthy.

In her article Zoë delves into the history of the five-a-day campaign and comes to the conclusion that it was originally started as “a programme to help with cancer in some non-quantified way”.  She also hints at vested interests being involved, noting that it was “an excellent commercial venture for all the companies involved at conception”.  

She adds that five-a-day has become embedded in our minds as a popular slogan, mainly thanks to a successful marketing programme, not because of any proven benefit of eating a certain number of fruits and vegetables a day. 

Zoë also debunks the notion that eating five-a-day leads to weight loss or has any protective effect against cancer.  

The biggest surprise, however, is that, according to Zoë, fruit and vegetables are not nearly as nutritious as we have been led to believe:

  • The pure forms of vitamin A (retinol), vitamin D3 and vitamin K2 are only found naturally in animal foods (meat, fish, eggs and dairy products).  
  • Seeds, nuts and their oils are the best source of vitamin E.
  • The best sources of the B vitamins are meat (especially organ meat), fish, milk and eggs.
  • Vitamin B12 is only found in animal products and therefore must be taken as a supplement by vegans (vegetarians can get B12 in milk and eggs).
  • Although they can be good sources, we don’t even need fruits and vegetables for vitamin C - kale and chicken liver are much better sources.
  • The best sources of calcium are dairy products and tinned fish.
  • Egg yolks, beef, cheese and liver are the best source of chromium.
  • Iron is best provided by organ meats.
  • Iodine is found in abundance in fish and kelp.
  • Magnesium and manganese are plentiful in nuts and whole grains.
  • Organ meats, fish and shellfish are good sources of selenium.
  • Zinc is found in oysters, liver, meat, cheese and fish.
  • Potassium is the one mineral for which fruits and vegetables are the best sources; it can however also be found in all of nature’s foods.

TIP: Take a look at the comparison tables for vitamin and mineral content of foods on Zoe Harcombe's website

To conclude in Zoë’s own words: “The first lesson in nutrition sets out that the body needs macro nutrients (fat, protein and carbohydrate – the need for the latter is debatable) and micro nutrients (vitamins and minerals).

“The best providers of the essential macro nutrients are animal foods – meat, fish, eggs and dairy. The best providers of vitamins and minerals are animal foods again, with seeds and a few non animal foods (kelp and peppers) being useful. The most nutritious foods on the planet, therefore, are animal foods.”

Is this "food for thought"? Share your experiences with us by emailing us at or in the comments below. 

Who is Zoe Harcombe?

Zoë is a graduate of Cambridge University in the UK and is currently doing a PhD in public health nutrition. She was awarded an MPhil in public health nutrition in December 2014. Zoë researches in the fields of nutrition, diet, dietary advice, diet-related health and obesity and reads, writes and talks about these subjects as many hours as possible, seven days a week. Her goal, as she explains on her website, is to reverse the obesity epidemic. She has clear views on how it started and what we need to do to stop it and these were published in 2010 in the 134,000 word book: The Obesity Epidemic: What caused it? How can we stop it?

Read more:
Carb and sugar addiction fuelling SA's obesity epidemic

Brain scans confirm food addiction

'Tim Noakes diet' comes out tops


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