Can you really survive eating nothing but POTATOES for a year?

In last year's blockbuster film The Martian, Matt Damon’s character, Mark Watney, is stranded on the red planet with nothing to eat but spuds.

And earlier this year, an Australian 36-year-old with a self-diagnosed 'food addiction' decided to follow the same diet to improve his health.

Aiming to lose weight and to train himself to see food as fuel rather than comfort and entertainment, Andrew Flinders Taylor decided to eat nothing but potatoes for a year.

‘I’m being supervised by a doctor and dietitian and getting supervised by a doctor. I’m getting all of the nutrients I need by eating potatoes,’ he told MailOnline earlier this month.

But can man live on potatoes alone? And could he have chosen a better single food to live on?

Writing for The Conversation, Dr Jennie Jackson, a nutrition and dietetics lecturer at Glasgow Caledonian University says Mr Taylor may be getting enough energy, but will lack essential nutrients like zinc, B12 and omega-3.

In last year's blockbuster film The Martian, Mark Watney (played by Matt Damon) is stranded on Mars with nothing to eat except potatoes he has grown from his own excrement.

Mr Watney has to survive for more than a 100 days before being rescued - and so found a way of growing potatoes in Mars soil and human compost (right). He then ate them every day with other NASA supplies (left)

Andrew Flinders Taylor has vowed to only eat potatoes for the entire year as part of a bizarre project to overcome an eating addiction.

pernicious anaemia to irreversible nerve damage.

Here, she describes the pros and cons of the potato-only diet...

The beginning

Just over a month into the diet, Mr Taylor posted a photo on Facebook of some unfinished mash potato on his plate.

This is a nice illustration of 'sensory-specific satiety' – the theory that the pleasure we take in consuming a single food goes down as we eat more of it, so we stop eating so much.

He is probably feeling the benefits of his weight loss (10kg in the first month), with increased energy levels, and already will have reduced his chances of developing diabetes and other chronic conditions. 

But what will happen in the long term?

Enough protein and fat?

Eating around 3kg of potatoes a day will provide just over 2000kcal, a reasonable amount for a man of his size aiming to lose weight.

But while potatoes are an excellent source of carbohydrates and fibre, he may struggle to get enough protein.

A 120kg man may need up to 90g of protein, but this diet will provide only 60g.

When he began the challenge Mr Taylor weighed in at 151.7kg (pictured). Although his focus was never on weight loss, he managed to lose 10kg within the first 28 days.

Proteins are made up of a range of amino acids, including some that must be supplied in our diet, and potatoes contain a surprisingly good balance of these.

But, despite spuds providing a good balance of amino-acids, there simply won’t be enough of them in Mr Taylor’s diet.

Potatoes are also low in fat (only 9g per 3kg), so Mr Taylor’s diet doesn’t supply enough of the two essential fatty acids (linolenic and linoleic acid), nor does it provide enough fat to aid the absorption of fat soluble vitamins: A, D, E and K.

We should also eat foods containing ready-made long-chain omega-3 polyunsaturated fatty acids, of which the only reasonable dietary source is oily fish.

These fats have specific structural and functional roles in cell membranes, can act as hormones, and help to control blood pressure.

Vitamins and minerals

Mr Taylor will get enough thiamine, niacin, vitamin B6, folate, vitamin C, potassium, magnesium, phosphorus and copper, even allowing for losses of these nutrients during cooking.

Also, he has boosted his chance of getting enough vitamins A and E, iron and calcium by agreeing to include sweet potatoes in his diet. But his diet lacks vitamins D and B12.

Exposure to sunshine in Australia means that he should be making enough vitamin D, but unless he takes a supplement his stores of vitamin B12 may well run out before the end of the year.

Prolonged deficiency will result in pernicious anaemia, which can lead to serious complications.

Pernicious anaemia is a disorder where the body cannot make enough healthy red blood cells due to the deficiency, which can lead to serious complications.

Lack of vitamin B-12 could also result in irreversible nerve damage.

By agreeing to include sweet potatoes in his diet, Mr Taylor has boosted his chance of getting enough vitamins A and E, iron and calcium.

Since he is allowing himself some seasonings, yeast extract would be a good choice, to top up levels of some of the other B vitamins, including biotin and riboflavin (vitamin B2).

A lack of these will affect the way that he can use the energy from his food.

Also, his diet will provide only around 6mg of zinc and he will need up to 9.5mg a day.

Zinc deficiency would become obvious in tissues with rapid turnover, such as the linings of our mouth, intestine and skin, resulting in reduced immunity and wound repair, and perhaps a loss of taste buds.

Other minerals that might be lacking in this diet include chloride, selenium and iodine, since levels of these depend on the soil in which the potatoes were grown.

Using an iodine-enriched salt would be helpful in terms of chloride and iodine, but his diet would probably supply only 30μg of selenium, low enough to cause deficiency in most people.

This could reduce immunity and lower reproductive capacity, as well as affecting thyroid function and antioxidant status.

Mr Taylor's diet of potatoes means he may struggle to get enough protein and be deficient in zinc.

Something better than potatoes?

Eating only one food probably won’t do any harm in the short term.

However, there is no known food that supplies all the needs of human adults on a long-term basis.

Since Mr Taylor is determined to follow a one-food diet, then potatoes are probably as good as anything, as they contain a wider range of amino acids, vitamins and minerals than other starchy foods, such as pasta or rice.

If he had chosen a single animal-derived food, he would have had no fibre in his diet and a poor intake of various vitamins, minerals and antioxidants.

Fruits and non-starchy vegetables are very low in protein and fat, meaning he would have to plough through a huge amount to get enough sustenance.

Green is not always healthy

As a final caution, potatoes produce solanine, a glycoalkaloid poison.

The amount in tubers of commercial varieties is generally low, but potato tubers that have been damaged in some way, or stored in the light, become green and produce more solanine.

Eating even small quantities of green potatoes can cause nausea and vomiting, cramps, fever, dizziness, headaches, convulsions.

The toxic dose doesn’t seem to have been definitively determined, and it’s not clear how well solanine is absorbed and metabolised, nor whether it builds up when eaten in small amounts over a long time.

Dr Jackson said eating only one type of food may aid weight loss as it triggers 'sensory-specific satiety' – the theory that the pleasure we take in consuming a single food goes down as we eat more of it, so we stop eating so much.

It’s clearly safe to eat 'normal' quantities of potatoes (up to around 300g) on a daily basis, but the safety of eating ten times this, for a whole year, has not been established.

But Mr Taylor should be comforted by the fact that potatoes are a staple food throughout the world, albeit part of a slightly more varied diet.

Eat to live, or live to eat?

One food is not enough, but we don’t need an enormous range of foods.

My great great grandfather, living in rural Aberdeenshire, had, like most of his contemporaries, a very limited diet of mainly potatoes, with oatmeal, kale and small amounts of fish and boiled beef.

He lived into his nineties and claimed never to be bored with his diet, saying: 'It’s just maet' (where the Scots word 'maet' refers to food in general, not just meat).

Food was fuel, rather than a form of comfort and entertainment. Perhaps that is the sort of relationship with food that Mr Taylor is trying to achieve.

(Editor:Kong Defang,Bianji)