Understanding processed foods

Oil and vinegar

Ultra processed foods have had a surge of negative publicity and quite rightly so! Blanket statements such as “processed foods are bad for us” or “never eat processed foods” are increasingly common. The proposed benefits of a diet devoid of processed foods range from the avoidance of food chemicals such as artificial sweeteners to being free of the “additive nature” of processed foods, to increase health and vitality. Particular emphasis is usually given to foods containing ingredients such as fat, saturated fat, added sugar, high fructose corn starch or trans fat.

Many people misuse the term “processed food”, leading to misinformation. Nearly all food and drinks are in fact processed in some way, by which I mean they are altered from their natural state by various methods, such as heating, salting, canning, fermenting, freezing and so on. These processes have evolved in order to make foods more accessible, convenient and palatable, and sometimes even safer. For example, a simple bread is made by following a recipe (flour, water, salt, yeast, oil) and then baking. Even without the addition of more complex ingredients, such as improvers or raising agents, the simple act of mixing and baking is processing. In the UK, the vitamins and minerals thiamine, niacin, calcium and iron are added to white bread to restore losses that occur during the milling of the grain. This simple restorative measure is also processing, yet it results in increased dietary intakes of these nutrients in the population, since bread is a popular food. In a similar manner, milk is a processed food – it is pasteurized (to ensure safety) and homogenized (to disperse milk-fat globules and avoid cream rising to the surface). In the UK, milk contributes around 26% to the population’s daily dietary calcium intake, while bread contributes approximately 14% to the daily intake of thiamine.

When discussing processed food intakes and health, it is useful to classify processed foods according to their degree of processing. The first group may contain minimally processed products: ready-prepared foods such as chopped veggies and frozen, pasteurized and canned foods. These tend to be whole foods, which have undergone some sort of process that doesn’t significantly alter their nutritional content. The second group, medium-processed foods, refers to oils, butter, flour, which are used as ingredients to make the third group, ultra-processed foods. This includes biscuits, bread, cereal, chocolate, sugary drinks, hot dogs, burgers and ready meals.

Many processed foods, particularly from the first group, are an essential convenience to time-poor families and can be a healthy choice. Frozen vegetables and fruits are often processed within hours of being picked so that hardly any nutrients are lost, and they can therefore be considered healthy choices. Processing also turns some otherwise inedible foods into palatable forms; for example, wheat on its own is pretty indigestible but through milling and refining is made into flour and then breads, a staple food for people all over the world.

Ultra-processed foods include foods that have come a long way from their natural state and which often have a lower nutritional content owing to heat exposure or removal of the nutritional portion. They tend to be energy-dense, containing a high number of calories thanks to the addition of sugars and fats, and may contain other additional ingredients such as salt, artificial sweeteners, additives and preservatives.

Processing can alter the nature of the food unfavourably, too, for example by increasing its glycaemic index. Such foods have increased dramatically in production and consumption in the past few decades, and it is often this group that people are referring to when they state that processed foods are bad for us. Current advice suggests individuals should carefully consider their intake of these ultra-processed foods, minimizing quantity. Balanced intakes and knowledge of ingredients are key: look out for hidden sugar, salt and fat. It is estimated that as much as three quarters of our salt intake comes from processed foods.

There is compelling evidence from the scientific community associating a high intake of some processed meats with an increased risk of bowel cancer. Processed meat includes sausages, ham, bacon, salami and pâté, and it is the method of preserving food by salting, smoking or curing that may introduce cancer-causing substances. People at risk are those eating more than 90g every day (which is equivalent to approximately four or five rashers of back bacon, three thick slices of ham or two sausages). This emphasizes the need for balance in the diet; individuals can make easy substitutes for processed meats to avoid eating them every day, for instance switching a ham for tuna.

We know that increased consumption of ultra-processed foods is associated with poorer health, namely increased tendency of over-consumption leading to risk of obesity and type 2 diabetes. This group of foods and drinks should not feature heavily in an individual’s diet, but including a range of lightly processed foods in the diet is not associated with negative health consequences. We need to be equipped with the knowledge to spot a decent processed food rather than demonizing the whole category.

The bottom line

Remove all processed foods from your diet if you wish, but you may find your diet very restricted, and more importantly you may have to look elsewhere to obtain enough nutrients to satisfy your body’s needs.

Try these simple swaps to reduce your intake of HPFs

Highly processedLess processed
Puffed or flaked cerealsNo sugar muesli or granola
Sliced breadSourdough
Soya meatballsMeatballs
Crab sticksCanned sardines
Puffed snacks (Skips, Wotsits, Quavers)Popcorn
Potato wafflesOven chips
Packet saucesJar sauces
ChutneyFermented pickles
Chocolate spreadPeanut butter
Extruded fruit (Yo Yo)Dried fruits
Bombay MixOlives
Soy sauceBalsamic vinegar

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