It’s no secret that eating foods that are high in added fat, salt and sugar may be harmful to our health. It can also increase the risk for some chronic conditions such as type 2 diabetes, cardiovascular disease and cancers. The Australian Dietary Guidelines recommend limiting intakes of these foods (e.g.  chips, lollies, chocolate, crackers, soft drinks and alcohol) to “only sometimes and in small amounts”. The most recent National Nutrition & Physical Activity Survey (2011-2012) found Australians got over a third (35%) of their total energy (kilojoule) intake from “sometimes” foods, most of which are ultra-processed.

So, what exactly are ultra-processed foods and how can we reduce our intake?

How are processed foods categorised?

Not all processed foods are harmful to health. Instead, they sit on a continuum from unprocessed/minimally processed to ultra-processed.

The art of processing foods is not new. Humans have been doing it for centuries. From cooking raw flesh over open fires to grinding wheat to make flour. Even bottling and preserving fruits and vegetables is a form of food processing.

The process of adding salt and sugar or heating and grinding foods helps extend shelf-life. It also makes the food more nutritious and safer to eat. However, in recent times food processing has taken on a new form. New technology has been created which combine foods with cheap, nutrient-poor ingredients such as additives, flavours and colours. Such innovation results in highly edible, attractive and convenient ultra-processed foods.  Ultra-processed foods (UPFs) was a term coined by researcher Dr Carlos Monteiro over a decade ago when he developed the slightly controversial NOVA classification system. The NOVA classification system classifies foods into one of four groups based on the degree of processing. The four groups are outlined below.

Unprocessed or minimally processed foods

This includes foods that have been frozen, washed or pasteurised. Food examples include washed and bagged salads, frozen fruit and plain milk

Processed culinary ingredients

Such as pressing, grinding or milling of foods. Food examples include oils, seeds, nuts, and sugar.

Processed foods

These are foods from either of the first two groups with the addition of salt, sugar or fat. Food examples include; canned fish, some types of bread and cheeses.

Ultra-processed foods

Include foods that have undergone extensive processing. These foods include chemicals such as artificial sweeteners, colours, and flavours. They are usually ready-to-eat and don’t need much preparation, such as soft drinks, cakes, biscuits, frozen ready-meals, ice creams and chips.

How does processed food affect diabetes?

High intakes of ultra-processed foods have been linked to a number of factors that may affect diabetes management. This includes eating higher amounts of energy (kilojoules or calories) as well as larger quantities of high glycaemic index (GI) foods.

A recent review found for every 10% increase in energy per day eaten from ultra-processed foods, there was a 15% increase in the risk of developing type 2 diabetes.

If you already have diabetes, excess energy intake can result in an increased waistline and higher insulin resistance. This may mean an increase to medications. It may also increase the risk of long-term diabetes-related complications.

Another study compared the energy intake of 20 adults, where half the participants ate a diet containing 80% ultra-processed foods, and the other half ate a diet of unprocessed foods. Participants were asked to eat as much or little as they wanted. Participants in the ultra-processed group ate an extra 2,100 kilojoules per day (the equivalent energy to a typical takeaway hamburger) and were also found to have a faster eating rate compared to the unprocessed group. Participants in the unprocessed diet group were found to produce more of a hormone responsible for feelings of fullness. These findings suggest eating a diet high in ultra-processed food leads to increased energy intake and lower levels of hormones responsible for feelings of fullness compared to eating a diet high in unprocessed food.

Blood glucose levels

Many ultra-processed foods contain little fibre and are high in added sugars. This means they are rapidly digested, causing blood glucose levels to rise quickly. These types of foods have a high glycaemic index (GI) which are known to spike blood glucose levels. Eating a diet that consists mainly of low GI foods may lead to improved blood glucose management for all people living with diabetes.

Recommendations

Despite the ease and convenience of ultra-processed foods, eating a diet of minimally processed, wholefoods will improve the overall quality of your diet and lead to better management of diabetes. Whilst it is impractical to completely remove all ultra-processed food from our diets, there are some practical tips you can follow to reduce your intake.

Tips to reduce your consumption of ultra-processed foods

1. Reduce temptation and availability – Don’t have ultra-processed foods such as cakes, chips or biscuits in your cupboards. Try grocery shopping online, so you are less likely to be tempted by treats and impulse-buys. If you go in-store to shop, keep to the outer edges of the supermarket as much as possible where you will find more fresh foods. The inner aisles of the supermarket are where you will find ultra-processed foods.

2. Be prepared and plan meals — take 20 to 30 minutes of your weekend to plan your meals and shopping list for the week. Taking time to plan your meals will save you money, as well as reduce the number of times you need to visit the supermarket. It will also decrease the likelihood of needing to reach for ultra-processed ready-meals when you get to that ‘5pm panic’.

If you’re stuck for meal ideas, look at the Healthy meal ideas fact sheet. It is full of breakfast, lunch, dinner and snack options. If you’re stuck for recipe ideas, look at the great selection of recipes from Diabetes Australia.

3. Save time by doubling the recipe – this will cut down the number of times you have to prepare meals during the busy week. Healthy lasagnes, chilli and soups make easy, nutritious meals. They are also easy to double quantities and freeze leftovers for another meal.

4. Choose wholegrains where possible – choose grainy products such as breads and crackers instead of wholemeal or white varieties. You can check the glycaemic index of carbohydrate containing foods using the GI search tool on the Glycaemic Index Foundation’s website, allowing you to find alternatives for your carb intake. 

5. Get savvy with food labels – food manufacturers are not required to label their food as ultra-processed, but they must list the ingredients used to make that food. Look at the ingredients list to work out whether a product is ultra-processed. Ultra-processed foods usually have five or more ingredients, with many of the ingredients containing foods that you would not find in a normal kitchen. Examples include: monosodium glutamate, soy lecithin or inverted syrup, just to name a few. Read the Understanding food labels for more information.

Take home messages

• There are four types of processed food categories according to the NOVA classification system. These include minimally/unprocessed, processed culinary, processed and ultra-processed.
• The art of food processing has been around for centuries. It extends shelf-life and makes food safer and more nutritious to eat.
• Australians are consuming too many ultra-processed foods in their diets.
• Reducing consumption of ultra-processed foods can lead to better blood glucose management, and reduced risk of diabetes-related complications.
• Eat a diet comprised of mostly minimally processed, whole foods such as fresh fruit and vegetables, fresh meats, poultry and seafood and low-GI wholegrains.
• Consider ultra-processed foods as ‘sometimes’ foods, only to be eaten in small amounts, and in moderation.
• There are a number of helpful resources to help you reduce your ultra-processed food intake listed below.

Where can I get more information?

• Healthy food choice fact sheet with a sample meal plan of healthy, minimally processed options
• Healthy meal ideas fact sheet
• Glycemic Index Food Database
• Understanding food labels fact sheet
• The NOVA Food Classification System handout
• Quality Carbohydrates and Health Report
• Low GI Diabetes Guide

By Libby Evans, MSc Human Nutrition