We all know that eating a lot of processed foods can be damaging to our health, but just how damaging and what should we look out for?

Recent research published in the BMJ has found ultra-processed foods are linked to an increased risk of obesity, high blood pressure, IBS (irritable bowel syndrome) and cancer. High consumption is associated with a risk of heart disease, weight gain and early death.

What are ultra-processed foods?

“Ultra-processed” is a term given to food as part of the NOVA food classification system. The globally recognised system divides food into four key groups depending on the amount of processing required to make the product.

The four groups are:

  1. Unprocessed / minimally processed foods
    Examples of unprocessed foods include fruit, vegetables, meat, eggs, milk and nuts. Minimal processing techniques include drying, pasteurisation, cooking or chilling.
  2. Processed culinary ingredients
    These include products that have undergone some processing to make them suitable for cooking such as oils, butter, sugar and salt. These ingredients are not designed to be eaten by themselves.
  3. Processed foods
    Processed foods are typically made from two or three ingredients and include preserved fruit and vegetables, cheese, fresh bread and canned fish.
  4. Ultra-processed foods
    Ultra-processed foods contain little Group 1 whole foods and undergo several processing methods such as hydrogenation, moulding, extrusion and pre-processing for frying. These food-like products typically have an ingredient list of more than 5 products including non-sugar sweeteners, hydrolysed proteins, emulsifiers, preservatives and hydrogenated oils. They’re typically ingredients you wouldn’t cook with.

According to the NOVA food classification system, examples of typical ultra-processed products are:

  • icecream
  • chocolate
  • lollies
  • cake mixes, biscuits, pastries, cake
  • bread and rolls
  • margarine, spreads and breakfast cereals
  • fruit yoghurt
  • fruit drinks, milk drinks, energy drinks, soft drinks, cocoa drinks
  • Nuggets, pizza, pre-prepared pasta, pies
  • Sausages, burgers, hot dogs and so on…

Growing evidence that ultra-processed foods can be harmful

Mark Lawrence, professor of public health nutrition at Deakin University said the evidence that ultra-processed foods can be harmful to our health is growing. “Anything with a long list of ingredients, including additives, is suspect,” he says.

The recent observational studies found the following:

The first study involved more than 105,000 middle-aged adults from France. The participants filled out six 24-hour dietary questionnaires with the researchers finding:

  • For every 10% of the diet that was made up of ultra-processed foods, there was just over 10% increase in the rates of cardiovascular disease, heart disease and cerebrovascular diseases including stroke.
  • The risk of these diseases reduced with the intake of more unprocessed or minimally processed foods.

The second study involved nearly 20,000 Spanish university graduates. These participants completed a 136-item dietary assessment with the researchers finding:

  • In people who consumed greater than 4 servings of ultra-processed foods per day, they had a 62% increased risk of death than those who ate less than two servings of ultra-processed food a day.
  • Each individual serving of ultra-processed food increased the risk of death by 18%.

Ultra-processed foods linked with weight gain

It’s not just heart health and early death researchers are concerned about. A new study published in the Cell Metabolism journal found that those who ate an ultra-processed diet are likely to overeat and in turn gain weight.

The participants of the study were found to eat approximately 500 more calories each day than those people whose diet emphasises healthy eating, rich in wholefoods.

These foods are often filled with added sugars, salt, refined carbohydrates and fat,” said David Katz, director of the Yale-Griffin Prevention Research Center in Derby. “The study itself found that people who ate ultra-processed foods tend to eat them faster and that they had lower levels of appetite-suppressing hormones than those who ate whole foods. As a result, they may have ended up eating more in order to feel satisfied.

Exactly why these ultra-processed foods lead to increased health risks and food intake hasn’t been answered. What we do know is these foods are often high in calories, sugar, saturated fat, salt and low in many beneficial nutrients such as fibre.

Lawrence said it’s pointless trying to find out what ingredients are harmful and increase our risk factors.

Rather than trying to reformulate these packaged foods to make them safer, we should be directing our efforts to making sure unprocessed or minimally processed foods are affordable and available.