Ultra-Processed Foods and Weight Loss: How They Could Be Stalling Your Progress

27 Apr

If you’ve ever felt like you’re “doing everything right” but still not seeing the weight loss you expect, ultra-processed foods (UPFs) might be playing a hidden role. These foods are everywhere - in supermarket aisles, lunchboxes, and even products labelled as healthy - and their impact on weight and health is gaining serious attention.

In the UK, we consume more UPFs per person than almost any other country in Europe, and emerging research suggests this could be a key factor in rising obesity rates and metabolic health issues [1]. Unlike basic food processing like freezing vegetables or fermenting yoghurt, ultra-processing involves industrial methods and additives that dramatically alter the food’s structure, nutrition, and how our bodies respond to it.

In this blog, we’ll break down what UPFs are, how they differ from other processed foods, and why they might be stalling your progress. You’ll also find practical tips to make healthier choices without giving up convenience or flavour.

What Are Processed and Ultra-Processed Foods?

Processed foods include any food that’s been altered from its natural state, through washing, chopping, freezing, fermenting, or adding ingredients for preservation or taste. Think frozen veg, canned beans, or natural yoghurt.

UPFs, on the other hand, are industrial formulations that typically:

Contain five or more ingredients
Include additives such as flavour enhancers, emulsifiers, and sweeteners
Are created in ways that can't be replicated in a home kitchen

Some examples include ready meals, fizzy drinks, packaged cakes, crisps, and sugary cereals.

UPFs can often be identified by their:

Long ingredient lists: Usually containing many additives (E numbers), such as emulsifiers, preservatives, colourings, and artificial flavourings.
Packaging: Often heavily packaged and marketed for convenience.
Nutritional labels: Typically high in added sugars, unhealthy fats, and salt.

The NOVA classification system places foods into four categories, and UPFs sit at the most processed end of the spectrum.

What Is The NOVA System?

The NOVA system is a classification framework developed by researchers at the University of São Paulo in Brazil in 2009. It was created to group foods based on the degree of processing they undergo. While it doesn’t categorise foods as inherently "healthy" or "unhealthy," it offers a clear and specific way to assess how much industrial processing has affected a food.

NOVA divides foods into four categories, with each group representing a different level of processing:

Unprocessed or Minimally Processed Foods: These are foods that have undergone little or no processing, such as fresh fruits, vegetables, and raw grains. They retain most of their natural nutrients and structure.

Processed Culinary Ingredients: This category includes foods like oils, butter, salt, and sugar, which are derived from natural sources but have been processed to be used as ingredients in cooking.

Processed Foods: These foods are typically made by adding sugar, salt, or fat to unprocessed foods to preserve them or enhance flavour. Examples include canned vegetables, cheeses, and cured meats.

Ultra-Processed Foods (UPFs): This is the final and most heavily processed category. UPFs are industrially manufactured with multiple ingredients, many of which are not commonly found in a typical home kitchen. They often contain additives like preservatives, sweeteners, and artificial flavours, and are designed to be convenient and highly palatable. Examples include ready meals, sugary drinks, and packaged snacks.

The NOVA system is particularly useful for understanding trends in global diets and assessing public health, but it also provides valuable insights into how food processing impacts the nutritional quality and health implications of what we eat.

The Spectrum of Food Processing

Food processing exists on a spectrum, ranging from minimal alterations to extensive industrial processing. The extent of processing largely depends on the number of ingredients, additives, and methods used during production. Almost any whole, unprocessed food can be transformed into an ultra-processed version through various industrial techniques.

Take corn, for example. Here’s how it progresses along the processing spectrum:

Unprocessed: Fresh corn - The natural form of the food, without any alterations.

Minimally Processed: Frozen corn or corn flour - The corn is processed for preservation, such as freezing or grinding, but retains most of its original nutritional value.

Processed: Cheesy corn chips - Corn is combined with added fats, salt, flavourings, and often preservatives to create a convenient snack, but it still contains recognisable ingredients.

Ultra-Processed: High fructose corn syrup - This heavily processed ingredient is derived from corn and used in many sugary foods and drinks. It undergoes chemical modifications and contains additives that are not typically found in home kitchens.

As you move along the spectrum from unprocessed to ultra-processed, the food typically loses some of its natural nutrients and may gain additives or chemicals designed to enhance taste, appearance, or shelf life. Understanding this spectrum can help clarify how different foods impact both our health and our waistlines.

Why Are UPFs Problematic for Weight Loss?

UPFs can present significant challenges when it comes to losing weight. Their composition and effects on the body make it harder to control calorie intake and maintain a balanced diet. Here’s why:

Nutritional Content: UPFs tend to be high in calories and unhealthy fats and sugars, while low in essential nutrients.

Satiety: They may not be as satiating as whole, unprocessed foods, leading to overconsumption.

Taste and Texture: UPFs are often designed to be highly palatable and addictive, making it easier to eat large portions.

Displacement of Healthy Foods: Eating UPFs may displace healthier food choices, reducing overall dietary quality.

While consuming UPFs occasionally may not be a major issue, regularly eating them can lead to increased calorie intake, cravings, and weight gain. Their combination of low nutritional value and high energy density makes weight management more difficult, especially in the context of a diet high in processed foods.

In fact, several studies have demonstrated a positive correlation between UPF consumption and weight gain [2].

The Negative Impact of UPFs Beyond the Scale

While weight gain is often the most visible consequence of a diet high in UPFs, the damage goes far deeper. Diets where UPFs make up 80% or more of total intake have been linked to a wide range of serious health risks, many of which develop silently and are difficult to reverse.

Metabolic and Cardiovascular Risks

High UPF consumption is strongly associated with type 2 diabetes, insulin resistance, high blood pressure, and abnormal cholesterol levels (dyslipidaemia). These metabolic disturbances not only hinder weight loss but also significantly raise the risk of heart disease, stroke, and other cardiovascular events. The excessive trans fats, added sugars, and salt commonly found in UPFs contribute to arterial stiffness, elevated LDL cholesterol, and hypertension [3].

Nutrient Deficiencies

UPFs tend to displace whole, nutrient-rich foods like fruits, vegetables, legumes, and whole grains. As a result, diets high in UPFs are often low in essential vitamins, minerals, fibre, and antioxidants - key players in supporting metabolism, digestion, and immune function.

Gut Health and Inflammation

Many UPFs contain additives, emulsifiers, and artificial ingredients that may damage the gut microbiome and increase intestinal permeability (also known as "leaky gut"). This can fuel chronic inflammation, disrupt appetite regulation, and contribute to conditions like irritable bowel syndrome (IBS) and autoimmune disorders. You can read more about the impact of processed foods on gut health here.

Increased Mortality Risk

Perhaps most concerning, research suggests a clear link between high UPF intake and early death. A 2019 study published in the British Medical Journal found that those with the highest UPF consumption faced an 18% higher risk of premature death, even when overall diet quality was taken into account [4].

A Closer Look at the Latest Evidence

Recent insights from the UK’s Scientific Advisory Committee on Nutrition (SACN) reinforce growing concerns around UPFs. In a comprehensive review of existing research, including systematic reviews and long-term cohort studies, SACN found a consistent pattern: higher consumption of UPFs is linked to a greater risk of a wide range of serious health issues [5].

The most robust evidence points to increased rates of obesity, type 2 diabetes, cardiovascular disease, and certain cancers among individuals with high UPF intake. Specific food categories - such as sweetened beverages and processed meats - were identified as particularly damaging.

While most of the data comes from observational studies, one randomised controlled trial included in the review did find that participants eating a diet rich in UPFs gained more weight than those consuming a diet based on unprocessed ingredients. However, the small scale of the trial means these findings should be interpreted with caution.

Taken together, SACN’s update adds weight to the argument that UPFs aren’t just a concern for waistlines - they represent a broader public health issue with far-reaching implications.

Are All UPFs Bad For Us?

It’s important to distinguish between different types of processed foods - many are not inherently unhealthy. Minimally and moderately processed foods are often altered for reasons such as preservation or convenience, yet they retain most of their nutritional value. These foods can be valuable additions to a balanced diet and can help streamline meal preparation.

While UPFs should generally be limited due to their lower nutritional quality and higher content of additives, not all processed foods are detrimental to health. Some, such as high-fibre and fortified options, may provide essential nutrients and pose little risk when consumed in moderation. For instance, wholegrain breakfast cereals, plant-based milk alternatives, and certain plant-based products can offer valuable nutrients and are not typically linked to negative health outcomes.

In fact, many processed foods can be part of a healthful eating plan, including:

Frozen fruits and vegetables
Frozen meat and fish
Canned beans, lentils, and chickpeas
Pre-cut vegetables and bagged salads
Pasta and noodles
Nut and seed butter
Hummus
Tofu
Yoghurt
Cottage cheese

Even some prepared meals, such as soups and stir-fries, can be nutritious if they are made from whole foods with minimal additives.

It’s also worth noting that SACN’s findings acknowledge that not all UPFs are equally harmful. Some foods, like certain vegetarian alternatives, might have a lower risk profile, although more research is needed to better understand their long-term effects [5]. You can read more about plant-based diets and the link with UPFs here.

Benefits of Minimally Processed Foods

Although fresh, unprocessed foods are ideal, minimally and moderately processed foods can play a valuable role in a healthy, sustainable diet. Far from being something to avoid, they often provide practical advantages that support both nutrition and lifestyle goals.

1. Nutrient Density

Minimally processed foods typically retain much of their original nutritional value. Unlike ultra-processed options that are often high in added sugars, unhealthy fats, and empty calories, these foods still offer essential vitamins, minerals, and fibre.

2. Satiety and Blood Sugar Control

Thanks to their higher protein and fibre content, minimally processed foods are generally more satisfying. They help promote stable blood sugar levels and reduce the likelihood of overeating, making them a powerful ally for weight management and long-term health.

3. Time-Saving Convenience

Convenience doesn’t have to mean compromise. Items like canned legumes, frozen vegetables, and pre-cut produce significantly cut down on prep time while still contributing to a balanced meal. They’re especially useful for busy weeks or when cooking from scratch isn’t practical.

4. Support for Consistency

Making healthy eating sustainable is key. The ease and accessibility of minimally processed foods can help you stay on track with your dietary intentions, reducing the temptation to reach for less nourishing alternatives when time or energy is short.

In short, these foods strike a balance between nutrition and practicality, making it easier to maintain healthy habits in everyday life.

Making Healthier Choices

In today’s food landscape, completely avoiding processed foods isn’t realistic - but making more informed choices is entirely possible. With a few simple strategies, you can reduce your intake of UPFs while still enjoying convenience and variety.

1. Read the Labels

Check ingredient lists and nutrition panels for added sugars, excess salt, and unhealthy fats. Aim for products with fewer ingredients - preferably ones you recognise - and steer clear of those with long lists of additives and preservatives.

2. Prioritise Whole Foods

Whenever possible, build meals around whole, unprocessed ingredients such as fresh vegetables, fruits, whole grains, legumes, nuts, seeds, and lean proteins. These foods are naturally nutrient-dense and support overall health.

3. Choose Minimally Processed Options

Opt for items like natural peanut butter, plain Greek yoghurt, canned beans, and wholegrain bread instead of heavily processed alternatives. These foods offer the benefits of convenience without compromising nutrition.

4. Cook More at Home

Preparing your own meals gives you full control over what goes into your food. Use simple, whole ingredients and try batch cooking - following the 'cook once, eat twice' approach can save time and support healthier eating throughout the week.

5. Plan Ahead

Meal and snack planning can help you avoid last-minute choices that rely on convenience foods. Keeping healthy staples on hand makes it easier to stick to your intentions.

6. Stay Hydrated

Choose water, herbal tea, or black coffee over sugary drinks. Staying well hydrated supports appetite regulation and overall well-being.

7. Watch Out for Health Claims

Words like “natural”, “low-fat”, or even “organic” can be misleading. Always check the ingredients and nutrition label to get the full picture of what you're consuming.

Finally, it’s worth remembering that not all UPFs are equally harmful. Some fortified or fibre-rich options, such as certain vegetarian alternatives or plant-based milks, may still offer nutritional benefits.

If the bulk of your diet comes from whole and minimally processed foods, the occasional indulgence in a less nutritious UPF isn’t likely to derail your progress. Balance, variety, and informed choices are key.

Frequently Asked Questions (FAQs)

1. Do I need to completely cut out UPFs to lose weight?

Not necessarily. The goal isn’t perfection, it’s awareness and improvement. Reducing your intake of UPFs and replacing them with whole, minimally processed alternatives can make a big difference to your weight loss, energy, and health without needing to be all-or-nothing.

2. How can I tell if a food is ultra-processed?

A good rule of thumb is to check the ingredients list. If it contains things you wouldn’t use at home - like emulsifiers, artificial sweeteners, hydrogenated oils, or preservatives, it’s likely ultra-processed. The longer the list and the more unfamiliar the ingredients, the more processed the product tends to be.

3. Are plant-based meat alternatives considered ultra-processed?

Many are, yes. Some plant-based meats contain a long list of additives, flavourings, and texture-enhancing ingredients. While they can be useful in moderation, they’re best enjoyed occasionally and balanced with whole plant-based foods like beans, lentils, tofu, nuts, seeds, and vegetables.

4. How can I start reducing UPFs without feeling overwhelmed?

Start small. Swap sugary breakfast cereals for oats, choose wholegrain bread over white, cook a few more meals from scratch each week, and build your meals around vegetables, legumes, and wholegrains. Gradual, consistent changes are more sustainable than a complete overhaul.

Conclusion

UPFs are more than just a dietary trend, they’re a growing concern in public health and a potential roadblock on your weight loss journey. While they may offer convenience, their high levels of additives, sugars, and unhealthy fats can make it harder to manage your appetite, energy levels, and long-term health.

The good news? You don’t need to eliminate all processed foods, just become more aware of what you’re choosing. By prioritising whole and minimally processed options, you can support your metabolism, reduce cravings, and make consistent progress towards your goals.

At the WLA, one of our core principles is a reduction in processed foods and added sugars, encouraging whole, minimally processed foods. This approach not only supports sustainable weight loss but also promotes overall well-being. You can read more about the WLA Nutrition Formula here or learn more about our Shift and Sustain programme here.