Food discussions / Let's talk

A look into Horizon’s episode on The Honest Supermarket

Updated 10th January 2021

Horizon is a series of programs run by BBC Two in the UK and is a documentary series looking into different aspects of science and philosophy. The series first launched in 1964, spanning 54 series now and over 1200 episodes. On 8th July, there was an episode titled The Honest Supermarket: What’s Really In Our Food? This post will discuss the key parts discussed in the episode.

NOTE: This is a fairly long blog post and there are spoilers below to the TV program contained.

Bottled water

The first topic covered surrounds bottled water. Under very control conditions, tap water has fewer microplastics compared to plastic bottled water. The program did state that a more comprehensive study would need to take place to say definitively whether this is the case. There is no international definition for microplastics, but only ‘microplastics smaller than 150 μm, [about the diameter of hair or paper] may [move] across the gut [wall, thereby affecting the rest of the body]. The absorption of these microplastics is expected to be limited (≤ 0.3%). Only the smallest fraction (size < 1.5 μm) may penetrate deeply into organs’ [1]. Microplastics can be airborne too, as fibres, for example, so removing any traces of microplastics is hard. There has not been any detailed research so far into how microplastics will affect humans long term.

Another point was the number of bacteria or microorganisms present in bottled water versus tap water. As tap water is treated with chlorine in the UK, there are fewer bacteria compared with bottled water [2]. This is also compounded by the fact that bacteria can grow once the bottle is opened and at high temperatures [3]. One can argue that perhaps the bacteria in bottled water is preferable to tap water. It’s worth mentioning that the amount of bacteria in either is very small. I personally will continue to drink tap water as I don’t want to see more plastic being created and left for future generations to deal with.

Food labelling

Green food

The next part looked into a lack of regulation on food labelling. Many of us buy products from the supermarket shelf from just looking at what’s written at the front of the packaging. Terms such as ‘natural’ being used in products that contain synthetic ingredients, or where blueberry breakfast bars are labelled as such at the front despite containing mostly cranberries were mentioned. It is shocking that we are outright being lied to by the main packaging text. As consumers, we can and should check what’s inside a product by looking at the list of ingredients on the side or the back of a product. These are listed in descending order with the main ingredients listed first.

In addition to this, I think it’s important to look at the nutritional content of what we consume. Often a product will highlight these at the front of the packaging using the traffic light system, but these are often shown with serving size suggestions. Many people overlook this information and assume it’s for the entire product. Recommended calorific intake is also another one we need to take into account, as the recommended daily allowance is usually for an adult woman [4]. We should all be more careful about choosing what products we purchase and eat. Next time you are at the shops, take a look at the back of the item before popping it into your basket/trolley.

Freshness of fish

The program found that fish that is in the refrigerated section of a supermarket can be as old as 20 days from the day it was caught (although some of this degradation in freshness might be a breakdown in the supply chain of keeping the fish at its optimal condition). You can say that some of the reason why fish can taste bland or even bad is due to its lack of freshness. A lot of fish in the refrigerated section has been frozen, then defrosted. As per EU regulation 1169/2011, the fact they are defrosted has to be included in the packaging, although this is not prominent. Chivers recommends that you buy frozen fish instead, as the fish would have suffered less degradation.

Another thing I wish to add to this is the presence of microplastics in our seafood. We hear about plastic in our oceans affecting sea creatures, so it should be no surprise that this also affects the seafood we eat. Over-fishing is also something to bear in mind. Eels/unagi are completely unsustainable in the UK, yet I still see them on many menus, particularly Japanese restaurants. The Marine Conservation Society provides some guidance on sustainable fish in the UK. You can also use this as an app on your phone if you search for the ‘Good Fish Guide’.

Pesticide use

The use of pesticides on our fruit and veg is widespread in commercial farming techniques. According to the Pesticide Action Network (PAN), UK, 40% of UK food contains pesticides. Looking at just fruit and vegetables, this figure rises to 60%+. The fear with our consumption of these foods is how the residue affects people. Looking at data from Fera Science Limited, it looks like pesticide use by weight has been massively reduced since 2006, but there has been an 11% increase in the pesticide-treated area and a 4% increase in the area grown in the United Kingdom between 2011 and 2017 [5].

In the program, one expert mentioned that we don’t consume enough residual pesticide in our food to worry about it. He mentioned a study was done in Denmark in 2019 which found that a glass of wine every seven years is about the same risk as pesticide residue [6].

The PAN, UK argues that although individually, the chemical compounds which make up various pesticides appear to have no effect on humans, together the cocktail can potentially be bad. Organic farming has strict regulations which try to limit pesticide use. ‘300 pesticides can be routinely used in non-organic farming [whereas]  organic farmers are permitted to use just 20 pesticides, derived from natural ingredients including citronella and clove oil, but only under very restricted circumstances. Organic farmers are permitted to use just 20 pesticides, derived from natural ingredients including citronella and clove oil, but only under very restricted circumstances’ [7].

The PAN, UK have created a pesticide guide which recommends a list of top 12 fruit and vegetables you should ideally eat organically, and a bottom 12 which aren’t affected heavily by pesticide residues. Soil Association also states that ‘60% of wholemeal bread samples tested by the Defra committee on Pesticide Residues in Food. Glyphosate’s manufacturers insist the levels in our food are safe. But a report by the World Health Organisation’s International Agency for Research on Cancer has concluded that glyphosate is a ‘probable carcinogen’. And research published since the IARC report suggests there is no safe level of glyphosate in food’ [7].

Environmental cost

A family’s shopping was analysed for this portion, which looked at the effect each product had on the environment in terms of carbon emissions. The family was asked to put their shopping in order from high carbon on one end of the table, to low carbon on the other end. The tactic used was to place things which were produced in the UK on the low carbon side. Berners-Lee then proceeded to reorganise the table noting the following:

  • Bananas and other hardy fruit and vegetables UK can be placed on the lower carbon side, as even though they are grown far away they would have been ferried rather than flown across, which uses fewer carbon emissions. Melons, apples, pears, and pineapples are also relatively low carbon. Berries outside the UK are high carbon.
  • Wine is also relatively low carbon as they are ferried across too. Moreso if they are also bottled in the UK, as the glass itself wouldn’t have needed to be transported too.
  • Beef and lamb are high carbon. Dairy is also relatively high carbon. I’ve explained the details of this in my post about 8 Easy Actions to Combat Climate Change, but effectively growing large animals uses a lot of resources which affect the environment negatively.
  • Bread is the UK’s most wasted food. It is important that we try to reduce food waste so that the effort and resulting environmental impact it had is not wasted.

It’s good that these key issues were highlighted. However, I could not look past the amount of plastic packaging also used in all the items purchased. Plastic can take up to 1000 years to decompose. The last thing we want to do is to add to the amount of plastic the Earth has. There are some plastics such as crisp packets which can be recycled via the TerraCycle scheme. Where possible, I would suggest buying things without plastic packaging, to begin with.

Convenience food

The program states that a recent study found that half of all food purchased in the UK is classified as ultra-processed. This is partially driven by consumers wanting cheaper food at a convenience. Such additives include some of these ingredients:

  • Preservatives – Makes food safer for longer
  • Emulsifiers – Makes ingredients blend together better
  • Antioxidants – Stops discolouration
  • Flavourings – Some contain items which make the food look more glossy

In recreating a supermarket pepperoni pizza, around 25 ingredients were used compared to a home-cooked one which would contain around 6 ingredients. Sodium nitrite is used in a lot of processed meat to give it a pinkier colour. When consumed at high levels. it has been linked to increased levels of bowel cancer by the World Health Organisation [8]. The other additives are marked as safe for consumption, although there have been no long term studies which prove or disprove this. In addition, the program notes that many of these additives are fattening, high in sugar or high in salt and lacking in nutrients. They are essentially energy-dense empty calories.

As consumers, we do have some power to affect this. We think that cooking from fresh takes time and effort. There may be an initial cost in learning how to cook from scratch, but there is plenty you can make that doesn’t take extra time. I’m a huge fan of the Roasting Tin books by Rukmini Iyer for this reason. Stir-fries and salads are also fairly simple to prepare and make. Bulk cooking is key and your freezer is your friend.

Palm oil

Palm oil is used in many of our goods from biscuits and cakes to pet food and toiletries like toothpaste and shampoo. Many of us have heard about the effects on orangutans from Iceland’s Christmas advert in conjunction with Greenpeace. Large areas of rainforest are being cleared to make room for palm oil plantations. According to Iceland, rainforests count for 50% of our biodiversity.

The reason why palm oil is so popular is that it has a high yield compared to alternatives. Oil can be extracted not just from the outer layer of the substance, but from the nut/kernel. You get hundreds of these fruits on each palm tree and each palm tree takes a relatively low amount of space. It takes a tenth of the space compared to growing soya. Palm oil also separates easily into different components and thus used in different products.

Looking at this, it would appear that palm oil is the miracle product. As alternatives include animal fats or plants which don’t produce as much yield, economically it is brilliant. Whatever palm oil is replaced with, it could potentially have a worse impact on our environment. I personally don’t think it’s feasible to remove palm oil completely. Where possible, if a product doesn’t contain palm oil, seek out alternatives which contain palm oil from sustainable sources. My thoughts on this are to reduce its use massively, where possible, and not eating processed foods like biscuits and cakes will help towards this. I also feel a large part of many problems on the Earth is a case of massive populations and the Earth struggling to supply enough resources for everyone.


There’s been a surge lately in sugar replacements in the supermarket, including coconut sugar, agave syrup, and fructose. Refined white sugar is obviously more processed than some alternatives like honey, but it is important to know that both contain sugar and replacing one with the other is not necessarily healthier. The latter, however, can contain extra nutrients. The program ran a brief test looking at different sugars with date syrup having the least spike and coconut sugar having a worse effect than refined sugars. It’s worth noting that these tests weren’t highly controlled as each person took one sugar substance, so I would take these results with a pinch of salt. The best sugars for us are those found in fresh fruit, where you won’t suffer a massive blood sugar spike. At the end of the day, sugar is sugar and we should be limiting these to a suitable amount rather than look for quick fixes.

Influences at the supermarket

The final part of the program looks at supermarket layouts and how psychology plays a part in this.

  • Fruit and vegetables are placed at the beginning. By buying healthy stuff at the beginning, it tricks the brain so you can justify the unhealthy stuff later.
  • Essentials like bread, milk, and tea are usually found separate from each other, meaning you need to traverse the whole supermarket. It’s harder to just grab and go.
  • Wine manufacturers can sometimes use heavier bottles to give you the feeling that you are getting a good quality product.
  • Music can affect what products we choose. E.g. french music for wine.

A good way of combatting this is to go in with a set shopping list, this way you will be less tempted to buy things you don’t need.

Final words

You have reached the bottom of this blog post! Thank you for reading all of this and hope the information provided has given you some food for thought. Please leave any comments below if you wish to add your opinions on any of the issues covered. There is a lot to cover and as a person, it can be hard to make the right choices. All we can do is try and do bits and hope everyone tries to make better decisions where they can.


[1] Presence of microplastics and nanoplastics in food, with particular focus on seafood. (2016). EFSA Journal, [online] 14(6). Available at: [Accessed 15 Jul. 2019].

[2] (2019). Water and health. [online] Available at: [Accessed 16 Jul. 2019].

[3] Raj, S. (2019). Bottled Water: How Safe Is It?. [online] Available at: [Accessed 16 Jul. 2019].

[4] (2019). Reference intakes explained. [online] Available at: [Accessed 24 Jul. 2019].

[5] Garthwaite, D., Barker, I., Mace, A., Parrish, G., Ridley, L. and Macarthur, R. (2019). Pesticide Usage Survey Report 281 Outdoor Vegetable Crops in the United Kingdom 2017. [ebook] Land Use & Sustainability Team, Fera Science Ltd, p.1. Available at: [Accessed 24 Jul. 2019].

[6] Larsson, M., Sloth Nielsen, V., Bjerre, N., Laporte, F. and Cedergreen, N. (2018). Refined assessment and perspectives on the cumulative risk resulting from the dietary exposure to pesticide residues in the Danish population. Food and Chemical Toxicology, [online] 111, pp.207-267. Available at: [Accessed 24 Jul. 2019].

[7] (2019). Reduce your exposure to pesticides | Soil Association. [online] Available at: [Accessed 24 Jul. 2019].

[8] (2019). Nitrite (JECFA Food Additives Series 50). [online] Available at: [Accessed 28 Jul. 2019].

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