Ultra-processed foods (UPF) are unequivocally associated with 32 detrimental health problems according to the largest review of its kind worldwide.

The findings show UPFs cause increased risks of heart disease, cancer, type 2 diabetes, adverse mental health outcomes, and premature mortality – or early death.

This groundbreaking review of evidence emerges as the nation becomes more aware of ultra-processed foods such as cereals, protein bars, fizzy drinks, ready meals, and fast food.

What are ultra-processed foods?

Ultra-processed foods, such as packaged baked goods, snacks, fizzy drinks, sugary cereals, and ready-to-eat meals, undergo extensive industrial processing and often contain artificial colours, emulsifiers, flavours, and other additives.

These products are typically high in added sugars, fats, and/or salt but low in vitamins and fibre.

In the UK, ultra-processed foods make up more than half of the average diet.

For certain groups of people in the UK, particularly younger individuals and those with lower income, a diet consisting of up to 80% ultra-processed foods is not uncommon.

How did the research measure ultra-processed food consumption?

Estimates of UPF exposure were derived from food frequency questionnaires, 24-hour dietary recalls, and dietary history, measuring it as higher versus lower consumption, additional servings per day, or a 10% increase.

The researchers categorised the evidence as convincing, highly suggestive, suggestive, weak, or non-existent.

They also evaluated the evidence quality as high, moderate, low, or very low.

Convincing evidence indicated that higher UPF intake was associated with approximately:

Highly suggestive evidence also showed that greater UPF consumption was linked to:

  • A 21% higher risk of mortality from any cause
  • A 40 to 66% increased risk of death related to heart disease, obesity, type 2 diabetes, sleep disturbances
  • A 22% increased risk of depression

Evidence also suggested associations between UPFs and the following conditions:

  • Asthma
  • Gastrointestinal health
  • Some cancers
  • Cardiometabolic risk factors, such as elevated blood fats and reduced levels of ‘good’ cholesterol

The researchers cautioned that the evidence for these associations is still limited.

Direct relationship between UPFs and ill-health

The research involved nearly 10 million participants and highlighted the necessity for strategies aimed at decreasing exposure to UPFs, according to the researchers.

The authors stated: “Direct relationships were established between the consumption of ultra-processed foods and 32 health indicators encompassing mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic health outcomes.”

They further explained: “Increased consumption of ultra-processed food was linked with a higher risk of negative health consequences, particularly regarding cardiometabolic, common mental disorders, and mortality outcomes.

The researchers acknowledged several limitations to their review, including the inability to eliminate the influence of other unmeasured factors and variations in assessing UPF intake on their findings.

Some experts not involved in the study also pointed out that much of the research included in the review was weak and cautioned that the findings do not establish a causal relationship.

However, Dr Tulleken, an associate professor at University College London remarked that the findings are “entirely consistent” with a “vast number of independent studies” linking a diet high in UPF to various harmful health outcomes, including premature death.

“But the way they’re processed is also significant – they’re designed and marketed in ways that encourage excessive consumption – for instance, they’re typically soft and energy-dense and aggressively marketed, usually to disadvantaged communities.”

Charlotte Summers, a visiting scholar at Warwick Medical School, University of Warwick and Chief Operations Officer at DDM remarked “ultra-processed foods offer accessibility and last a long time; on the other, they carry a hidden cost to our health.”

“As we navigate our food choices, particularly during this cost-of-living crisis, it’s crucial to balance convenience with the nourishment our bodies truly need.”

The study, published in the BMJ, involved Johns Hopkins Bloomberg School of Public Health in the US, the University of Sydney and Sorbonne University in France.

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