Ultra-processed foods: practical guide to eating better

Ultra-processed foods now account for between 40 and 70% of daily calorie intake in countries like the UK, the US, and Australia. Randon Lambert, a registered nutritionist with over 15 years of clinical experience and seven books on nutrition, offers an evidence-based and non-alarmist framework for understanding what we are eating and how to improve it without overhauling everything at once.

What are ultra-processed foods?

The most widely used classification is the NOVA system, developed in Brazil by Carlos Monteiro. It divides foods into four categories based on degree of processing. Category 4 is the problem category: products containing emulsifiers, additives, preservatives, and other ingredients that would never appear in a home kitchen.

Not all ultra-processed foods are equal. A plant milk fortified with B12 and iodine is technically ultra-processed, but may be a valid option for people with allergies or nutritional deficiencies. The same applies to plant-based meat alternatives, which reduce the cancer risks associated with excessive red and processed meat consumption.

Why the food matrix matters

One of the key reasons the scientific community is concerned about ultra-processed foods is the concept of the food matrix. The calorie counts printed on packaging can be up to 30-40% inaccurate because the bioavailability of energy depends on the physical structure of the food.

A clear example: eating whole almonds means the body absorbs around 60-70% of their calories because the cell wall slows digestion. Ground almonds, with the cell wall already broken, deliver close to 100% of their calories much faster. This difference also affects blood sugar levels and gut bacteria, and explains why home-cooked meals consistently outperform ready meals in research even when calories and ingredients are identical.

The central role of fiber

Fiber is the biggest gap in most modern diets. Only 4% of adults in the UK reach the recommended 30 grams per day. A 2025 UCL study compared weight loss in people eating ready meals versus home-cooked meals with the same calorie counts and ingredients. Those cooking at home lost twice as much body fat.

During World War II rationing in the UK, the average daily fiber intake was 40-50 grams simply because people cooked their food. The solution is not fiber supplements but a return to whole foods. Practical ways to increase fiber intake include:

• Adding fruit and a handful of nuts to breakfast
• Choosing bread with at least 2.5 g of fiber per slice
• Building meals around legumes, seeds, and vegetables
• Preparing oats or avocado toast instead of packaged pastries or protein bars

How to read a label in the supermarket

For bread, one of the most heavily manipulated categories in the food industry, Lambert focuses on three numbers:

1. Fiber: ideally more than 2.5 g per slice.
2. Salt: less than 1 g per 100 g.
3. Sugar: no more than 1 g per slice.

Brown color is not a reliable indicator: a loaf can contain added dyes, high sugar, and very little actual fiber. Seeds on the surface are a bonus, not a guarantee.

On additives, six colorants are listed by the UK Food Standards Agency for their link to hyperactivity in children: allura red, ponceau 4R (E124), carmoisine, sunset yellow, quinoline yellow, and tartrazine. These appear mainly in sweets, confectionery, and brightly colored beverages.

Artificial sweeteners: not the solution

Lambert has updated her stance on artificial sweeteners in recent years. They are not directly harmful, but emerging data suggests they do not benefit gut bacteria, and the WHO now explicitly states they have no meaningful impact on weight loss. Obesity rates continue to rise despite their widespread use in products marketed as healthy alternatives.

A further concern is that the intense sweetness of these compounds maintains and reinforces a preference for very sweet foods. Lambert would rather have a smaller amount of real sugar than a daily drink loaded with stevia or similar sweeteners.

Practical steps to reduce ultra-processed food intake

Eliminating ultra-processed foods entirely is neither possible nor the goal. Lambert recommends a gradual approach:

• Start with breakfast: the easiest meal to control. Preparing oats or toast the night before takes less than five minutes.
• Cook once, eat twice: make larger batches of sauces or curry bases and freeze them to avoid relying on ready meals during the week.
• One cooking day per week: a single weekly session can significantly improve the nutritional quality of the rest of the week.
• Ignore social media noise: less than 2% of nutritional information on TikTok is accurate according to recent research. Learning to read labels is more useful than following viral trends.

Conclusion

Lambert's core message is not fear but concrete action. Adding one more home-cooked meal per week, learning two or three key numbers to look for on labels, and gradually increasing fiber intake are small changes with real and sustainable impact. Ultra-processed foods will not disappear from our diets, but we can make better choices among them and significantly reduce the ones most strongly linked to disease.