Ultra-processed foods are damaging your metabolic health. Here's why:

Abby Courtenay
Abby Courtenay
September 13, 2021

We’ve all heard that the food we eat today is nothing like the food our grandparents ate. While visions of franken-foods and poor farming methods may creep into your mind, when we say this, you may be surprised to hear that it is not run of the mill whole foods that we are referring to. Food consumption is leaning away from freshly prepared meals which are being actively displaced by ultra-processed foods (UPFs).

The problem with UPFs is that they contain little, if any, of the original intact food. They are essentially a formulation of ingredients derived from food and additives to create a food-like product. In the modern world, real food doesn’t stand a chance against UPFs because they are designed to be more durable, ready to eat, low cost and insanely delicious, leaving you wanting more. If that wasn’t enough, these products are also cleverly branded and aggressively marketed to gain consumer buy-in. Who doesn’t want their morning cereal to be an all-in-one that has been slapped with a few convincing health claims?

With this in mind, should consumers be avoiding processed foods altogether? The short and simple answer is that not all processing is bad. Some foods need to be altered from their natural state to make them suitable to store and safe to consume. Let’s explore how we classify various foods with regards to how they have been processed.

Minimally processed vs processed foods

Minimally processed foods (which are usually grouped with unprocessed foods) have occasionally been altered through minimally invasive techniques like pasteurization, removing inedible parts, roasting, boiling or freezing as well as crushing and drying. None of these processes adds extra salt, sugars, oil/ fats, or any other food substances to the original food. Some examples that spring to mind include rolled oatmeal, pasteurised milk or even a skinless chicken breast.

We may go a step further and add small amounts of processed culinary ingredients (like salt, sugar or oil) to this group. These products have been created using a variety of methods like pressing, refining, extracting or mining and are used to prepare and season our whole and minimally processed foods.

We can also combine foods from the first group and the second group to further increase their shelf-life and palatability to form processed foods. Think of foods that have been canned or bottled (with or without salt and sugar) or bread, cheeses and vegetables like sauerkraut that have been produced using non-alcoholic fermentation.

The main aim of this minimal processing is to extend their life, enable safe storage and also make preparation easier. If we avoided these processing methods, we would either eliminate a variety of foods from our diet (because they would just be too tedious to prepare) or we would literally be spending our lives in the kitchen.

Over the past few years, there has been a shift from celebrating (or demonising) single nutrients, foods and food groups towards placing focus on healthy eating patterns. We do not consume nutrients in isolation and it has become apparent that our regular eating patterns have synergistic effects on our health. Eating patterns that are revered worldwide for promoting health and longevity include the Mediterranean, Japan and Korea. The commonalities between these eating patterns are that the majority of their meals are made from a variety of unprocessed or minimally processed foods that are prepared, seasoned and cooked with some processed culinary ingredients with the occasional processed food thrown in for convenience (and a bit of taste!)

What are UPFs?

Where do UPFs fit in? As we mentioned, UPFs are food-like products. They are created by combining fractions of foods in ways that do not occur naturally. Whole, high yield foods like corn, wheat, soy, cane and beet, or ground-up animal carcasses are usually broken down into single ingredients like sugar, starches, fibre, oil/ fats and protein. Some of these substances are chemically modified through a variety of processes like hydrolysis or hydrogenation and ‘cosmetic additives’ are added to make the final product very tasty to eat (these are additives that make the final product more appealing or palatable).

These ingredients are then assembled into their food-like form through processes like extrusion, moulding and pre-frying. These items are then packaged through a variety of sophisticated methods into synthetic materials. So, how bad can UPFs be?

How do UPFs contribute to poor metabolic health?

Over the past few years, researchers have focused much of their attention on the health effects of consuming UPFs, as more than half of the food consumed in high-income countries is ultra-processed with middle and low-income countries quickly following suit. It is becoming increasingly clear that a high UPF diet has detrimental effects on metabolic health and promotes the development of obesity and other non-communicable diseases (NCDs). NCDs such as cardiovascular disease, type 2 diabetes and some cancers account for up to 70% of all deaths, worldwide! Curbing UPF consumption may be the key to drastically reducing that number.

Your metabolic health is strongly influenced by your body's sensitivity to insulin. If you are insulin resistant, it means that your cells are no longer sensitive to the insulin that your body is producing. As a result, you will have both high circulating insulin levels (which may predispose you to abdominal obesity) and high sugar (glucose) levels thus increasing your risk for type 2 diabetes and cardiovascular disease.

UPFs contribute to glucose intolerance, insulin resistance and type 2 diabetes through a variety of mechanisms. Here's the full list:

Have an unbalanced nutritional profile

One of the glaringly obvious effects of a diet high in UPF is that they displace more nutritious whole foods thus leading to poor diet quality (possibly with ‘hidden’ micronutrient deficiencies) and related diseases. In addition to this, the concentration of carbohydrates and sugars in UPFs is far higher than that found in whole or unrefined foods. UPFs are also often low in protein and fibre, meaning that the absorption of these sugars is rapid. Each time your blood sugar rises, your body responds by secreting insulin. The more sugar that you consume, the more insulin is needed. Eventually, insulin resistance sets in.

Contain food additives like carrageenan (E407) and sweeteners

Carrageenan is a product used to thicken, emulsify and preserve certain foods and drinks (especially highly processed vegetarian and vegan foods). Studies conducted in mice (and on human cells in the lab) have found that carrageenan may induce inflammation which may impair glucose tolerance, increase insulin resistance and prevent insulin signalling. All these can increase your risk for type 2 diabetes .

Non-nutritive sweeteners (like aspartame, sucralose and stevia), on the other hand, have been promoted in the past as a good alternative to sugar for those wanting to control their blood sugar levels and decrease their energy intake (mainly for weight loss). Studies are ongoing, but these sweeteners may not be the white knights they claim to be, with evidence from randomised control trials showing that people who routinely consume these sweeteners, may be at risk of having an increased BMI and cardiometabolic risk.

Contain neo-formed contaminants

Neo-formed contaminants are commonly found in UPFs due to the complex reactions between the various components during processing. An example of a neo-formed contaminant is polycyclic aromatic hydrocarbons (PAHs). These are formed when certain proteins are exposed to high temperatures or flames. In some populations, high levels of PAHs are positively associated with diabetes.

Heat treating can also increase the amount of advanced glycation end products (AGEs) in the diet. As with PAHs, AGEs are found in high levels in heat-treated animal-based products. AGEs have been associated with increased oxidative stress and inflammation and subsequently an increased risk for type 2 diabetes and cardiovascular disease.

May be exposed to contact materials like phthalates and bisphenol

Phthalates and bisphenol may be more concentrated in ready-to-eat UPFs that are heated or served in paper, plastic or cardboard. Bisphenol-A (BPA), for example, is found in epoxy resin which is used as an internal coating of cans. It protects the can from rusting and corrosion, but can migrate into the food during storage and processing, especially at elevated temperatures (11). Both phthalates and bisphenol are considered to be endocrine disruptors and have been linked with a higher risk of diabetes and insulin resistance.

Can increase your risk for unwanted weight gain

In addition to all this, UPFs have a direct dose-response with energy density which may contribute to unwanted weight gain, with abdominal obesity being one of the most important contributors to metabolic health (3). Even when we match a whole food diet with a UPF diet in terms of calories, macronutrients, fibre, sugar and sodium, the UPFs diet individuals still consume more than 500kCal/ day more energy! This highlights the addictive nature and low satiety power (aka the ability to keep you feeling full) of UPFs.

How to identify UPFs

So basically, UPFs are bad news! How are you going to go about identifying processed vs UPFs?

We don’t need to over-analyze every morsel of food we put in our mouths as we know that fresh fruits and vegetables (including potatoes and the like) are obviously not ultra-processed. The same goes for pasteurised milk and chilled meat cuts. It becomes quite obvious which foods are ultra-processed when we take a look at the ingredients listed on pre-packaged goods. If you notice an ingredient in the list which is never or very rarely used in the kitchen or is considered to be a ‘cosmetic additive’, then the food item in question may be ultra-processed.

Information on ingredients lists are unfortunately not standardised all over the world, but some food substances not used in home kitchens include hydrolysed proteins, soya protein isolate, gluten, casein, whey protein, ‘mechanically separated meat’, fructose, high-fructose corn syrup, ‘fruit juice concentrate’, invert sugar, maltodextrin, dextrose, lactose, soluble or insoluble fibre, hydrogenated or interesterified oil (2). Frequently used cosmetic additives include flavours, flavour enhancers, colours, emulsifiers and sweeteners.

Practical example

If a commercially available bread contains wheat flour, water, salt and yeast it is considered to be processed. If that list of ingredients also contains emulsifiers or colours, then it is considered to be ultra-processed.

Plain rolled oats are minimally processed. If it contains added sugar only it is considered to be processed and it also contains flavours and colours it is considered to be ultra-processed (e.g. flavoured instant oatmeal).

Summary

Food processing is not inherently ‘bad’, most food that we buy and eat has been processed to some extent. If we only ate unprocessed foods, we would be severely limited in our choices which could backfire on our health.

What we do need to do, is emphasise choosing foods that have been processed using harmless methods of preservation or even those that improve food quality (like non-alcoholic fermentation). The problem is not processing, it is ultra-processing. UPFs are food-like products. They trick us into thinking that they are equal to real food counterparts, but the truth is that there are several health hazards associated with consuming them.

Identifying UPFs is a skill every one of us should learn and when we know how to do this, it is our responsibility to reduce our intake and choose healthier alternatives. If we can do this, not only will we increase our overall nutrient intake (which is protective), but we eliminate the ingredients that can potentially do harm.

We’ve all heard that the food we eat today is nothing like the food our grandparents ate. While visions of franken-foods and poor farming methods may creep into your mind, when we say this, you may be surprised to hear that it is not run of the mill whole foods that we are referring to. Food consumption is leaning away from freshly prepared meals which are being actively displaced by ultra-processed foods (UPFs).

The problem with UPFs is that they contain little, if any, of the original intact food. They are essentially a formulation of ingredients derived from food and additives to create a food-like product. In the modern world, real food doesn’t stand a chance against UPFs because they are designed to be more durable, ready to eat, low cost and insanely delicious, leaving you wanting more. If that wasn’t enough, these products are also cleverly branded and aggressively marketed to gain consumer buy-in. Who doesn’t want their morning cereal to be an all-in-one that has been slapped with a few convincing health claims?

With this in mind, should consumers be avoiding processed foods altogether? The short and simple answer is that not all processing is bad. Some foods need to be altered from their natural state to make them suitable to store and safe to consume. Let’s explore how we classify various foods with regards to how they have been processed.

Minimally processed vs processed foods

Minimally processed foods (which are usually grouped with unprocessed foods) have occasionally been altered through minimally invasive techniques like pasteurization, removing inedible parts, roasting, boiling or freezing as well as crushing and drying. None of these processes adds extra salt, sugars, oil/ fats, or any other food substances to the original food. Some examples that spring to mind include rolled oatmeal, pasteurised milk or even a skinless chicken breast.

We may go a step further and add small amounts of processed culinary ingredients (like salt, sugar or oil) to this group. These products have been created using a variety of methods like pressing, refining, extracting or mining and are used to prepare and season our whole and minimally processed foods.

We can also combine foods from the first group and the second group to further increase their shelf-life and palatability to form processed foods. Think of foods that have been canned or bottled (with or without salt and sugar) or bread, cheeses and vegetables like sauerkraut that have been produced using non-alcoholic fermentation.

The main aim of this minimal processing is to extend their life, enable safe storage and also make preparation easier. If we avoided these processing methods, we would either eliminate a variety of foods from our diet (because they would just be too tedious to prepare) or we would literally be spending our lives in the kitchen.

Over the past few years, there has been a shift from celebrating (or demonising) single nutrients, foods and food groups towards placing focus on healthy eating patterns. We do not consume nutrients in isolation and it has become apparent that our regular eating patterns have synergistic effects on our health. Eating patterns that are revered worldwide for promoting health and longevity include the Mediterranean, Japan and Korea. The commonalities between these eating patterns are that the majority of their meals are made from a variety of unprocessed or minimally processed foods that are prepared, seasoned and cooked with some processed culinary ingredients with the occasional processed food thrown in for convenience (and a bit of taste!)

What are UPFs?

Where do UPFs fit in? As we mentioned, UPFs are food-like products. They are created by combining fractions of foods in ways that do not occur naturally. Whole, high yield foods like corn, wheat, soy, cane and beet, or ground-up animal carcasses are usually broken down into single ingredients like sugar, starches, fibre, oil/ fats and protein. Some of these substances are chemically modified through a variety of processes like hydrolysis or hydrogenation and ‘cosmetic additives’ are added to make the final product very tasty to eat (these are additives that make the final product more appealing or palatable).

These ingredients are then assembled into their food-like form through processes like extrusion, moulding and pre-frying. These items are then packaged through a variety of sophisticated methods into synthetic materials. So, how bad can UPFs be?

How do UPFs contribute to poor metabolic health?

Over the past few years, researchers have focused much of their attention on the health effects of consuming UPFs, as more than half of the food consumed in high-income countries is ultra-processed with middle and low-income countries quickly following suit. It is becoming increasingly clear that a high UPF diet has detrimental effects on metabolic health and promotes the development of obesity and other non-communicable diseases (NCDs). NCDs such as cardiovascular disease, type 2 diabetes and some cancers account for up to 70% of all deaths, worldwide! Curbing UPF consumption may be the key to drastically reducing that number.

Your metabolic health is strongly influenced by your body's sensitivity to insulin. If you are insulin resistant, it means that your cells are no longer sensitive to the insulin that your body is producing. As a result, you will have both high circulating insulin levels (which may predispose you to abdominal obesity) and high sugar (glucose) levels thus increasing your risk for type 2 diabetes and cardiovascular disease.

UPFs contribute to glucose intolerance, insulin resistance and type 2 diabetes through a variety of mechanisms. Here's the full list:

Have an unbalanced nutritional profile

One of the glaringly obvious effects of a diet high in UPF is that they displace more nutritious whole foods thus leading to poor diet quality (possibly with ‘hidden’ micronutrient deficiencies) and related diseases. In addition to this, the concentration of carbohydrates and sugars in UPFs is far higher than that found in whole or unrefined foods. UPFs are also often low in protein and fibre, meaning that the absorption of these sugars is rapid. Each time your blood sugar rises, your body responds by secreting insulin. The more sugar that you consume, the more insulin is needed. Eventually, insulin resistance sets in.

Contain food additives like carrageenan (E407) and sweeteners

Carrageenan is a product used to thicken, emulsify and preserve certain foods and drinks (especially highly processed vegetarian and vegan foods). Studies conducted in mice (and on human cells in the lab) have found that carrageenan may induce inflammation which may impair glucose tolerance, increase insulin resistance and prevent insulin signalling. All these can increase your risk for type 2 diabetes .

Non-nutritive sweeteners (like aspartame, sucralose and stevia), on the other hand, have been promoted in the past as a good alternative to sugar for those wanting to control their blood sugar levels and decrease their energy intake (mainly for weight loss). Studies are ongoing, but these sweeteners may not be the white knights they claim to be, with evidence from randomised control trials showing that people who routinely consume these sweeteners, may be at risk of having an increased BMI and cardiometabolic risk.

Contain neo-formed contaminants

Neo-formed contaminants are commonly found in UPFs due to the complex reactions between the various components during processing. An example of a neo-formed contaminant is polycyclic aromatic hydrocarbons (PAHs). These are formed when certain proteins are exposed to high temperatures or flames. In some populations, high levels of PAHs are positively associated with diabetes.

Heat treating can also increase the amount of advanced glycation end products (AGEs) in the diet. As with PAHs, AGEs are found in high levels in heat-treated animal-based products. AGEs have been associated with increased oxidative stress and inflammation and subsequently an increased risk for type 2 diabetes and cardiovascular disease.

May be exposed to contact materials like phthalates and bisphenol

Phthalates and bisphenol may be more concentrated in ready-to-eat UPFs that are heated or served in paper, plastic or cardboard. Bisphenol-A (BPA), for example, is found in epoxy resin which is used as an internal coating of cans. It protects the can from rusting and corrosion, but can migrate into the food during storage and processing, especially at elevated temperatures (11). Both phthalates and bisphenol are considered to be endocrine disruptors and have been linked with a higher risk of diabetes and insulin resistance.

Can increase your risk for unwanted weight gain

In addition to all this, UPFs have a direct dose-response with energy density which may contribute to unwanted weight gain, with abdominal obesity being one of the most important contributors to metabolic health (3). Even when we match a whole food diet with a UPF diet in terms of calories, macronutrients, fibre, sugar and sodium, the UPFs diet individuals still consume more than 500kCal/ day more energy! This highlights the addictive nature and low satiety power (aka the ability to keep you feeling full) of UPFs.

How to identify UPFs

So basically, UPFs are bad news! How are you going to go about identifying processed vs UPFs?

We don’t need to over-analyze every morsel of food we put in our mouths as we know that fresh fruits and vegetables (including potatoes and the like) are obviously not ultra-processed. The same goes for pasteurised milk and chilled meat cuts. It becomes quite obvious which foods are ultra-processed when we take a look at the ingredients listed on pre-packaged goods. If you notice an ingredient in the list which is never or very rarely used in the kitchen or is considered to be a ‘cosmetic additive’, then the food item in question may be ultra-processed.

Information on ingredients lists are unfortunately not standardised all over the world, but some food substances not used in home kitchens include hydrolysed proteins, soya protein isolate, gluten, casein, whey protein, ‘mechanically separated meat’, fructose, high-fructose corn syrup, ‘fruit juice concentrate’, invert sugar, maltodextrin, dextrose, lactose, soluble or insoluble fibre, hydrogenated or interesterified oil (2). Frequently used cosmetic additives include flavours, flavour enhancers, colours, emulsifiers and sweeteners.

Practical example

If a commercially available bread contains wheat flour, water, salt and yeast it is considered to be processed. If that list of ingredients also contains emulsifiers or colours, then it is considered to be ultra-processed.

Plain rolled oats are minimally processed. If it contains added sugar only it is considered to be processed and it also contains flavours and colours it is considered to be ultra-processed (e.g. flavoured instant oatmeal).

Summary

Food processing is not inherently ‘bad’, most food that we buy and eat has been processed to some extent. If we only ate unprocessed foods, we would be severely limited in our choices which could backfire on our health.

What we do need to do, is emphasise choosing foods that have been processed using harmless methods of preservation or even those that improve food quality (like non-alcoholic fermentation). The problem is not processing, it is ultra-processing. UPFs are food-like products. They trick us into thinking that they are equal to real food counterparts, but the truth is that there are several health hazards associated with consuming them.

Identifying UPFs is a skill every one of us should learn and when we know how to do this, it is our responsibility to reduce our intake and choose healthier alternatives. If we can do this, not only will we increase our overall nutrient intake (which is protective), but we eliminate the ingredients that can potentially do harm.