The numbers are in: Junk food’s toll on physical & mental health

 

Consuming ultra-processed food, commonly known as junk food, has been associated with a higher risk of more than 30 different adverse mental and physical health outcomes, according to a new study. The research highlights the wide range of health issues that eating this kind of food can cause.

We’re often told that to maintain good health, we need to eat well, which includes a balanced diet low in ultra-processed foods (UPF), which includes packaged baked goods and snacks, sweetened, carbonated drinks, candy, sugary cereals, and ready-to-eat products.

While many of us are well aware of the health risks associated with eating a diet high in UPF, we might not appreciate just how harmful they can be. Researchers have pooled the data from 45 distinct meta-analysis studies associating UPF with adverse health outcomes, providing a high-level summary – an ‘umbrella review’ – of the evidence.

The total number of participants included across the umbrella review was close to 10 million. All meta-analyses were published in the last three years, and none were funded by companies that produce UPF. The researchers categorized the evidence as convincing, highly suggestive, suggestive, weak, or no evidence. They also assessed the quality of the evidence as high, moderate, low, or very low. Overall, the data showed that higher exposure to UPF was consistently associated with an increased risk of 32 adverse health outcomes that spanned mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic health outcomes.

Convincing evidence showed that higher consumption of UPF was associated with around a 50% increased risk of cardiovascular disease-related death, a 48% to 53% higher risk of anxiety and common mental health disorders, and a 12% higher risk of type 2 diabetes. Highly suggestive evidence indicated that higher UPF intake was associated with a 21% greater risk of death from any cause, a 40% to 66% increased risk of heart disease-related death, obesity, type 2 diabetes, and poor sleep, and a 22% increased risk of depression.

There was limited evidence associating UPF with asthma, gastrointestinal health, some cancers and cardiometabolic risk factors such as high blood fats and low levels of ‘good’ cholesterol.

The study has generated a great deal of interest from researchers and those in the medical community. Charlotte Gupta, a research fellow at the Appleton Institute, Central Queensland University, thought that the research provided “convincing evidence” but asked that we consider why some people eat UFP.

“[F]or some people, such as shiftworkers working at night … there is a lack of availability of fresh foods or time to prepare any food, and so ultra-processed foods have to be relied on,” Gupta said. “This highlights the need for not only individuals to try reducing ultra-processed foods in our diet but also for public health actions to improve access to healthier foods.”

Melanie McGrice, a practicing accredited dietician, said that the study’s results accorded with her professional experience.

“In my role as a dietitian, I see so many people reliant on ultra-processed food,” said McGrice. “Some of the key factors impacting consumption of ultra-processed foods include perceived convenience, social influences, emotional eating and advertising. I’ve seen extraordinary results for individuals who I have worked with as a result of decreasing intakes of ultra-processed foods.”

And Clare Collins, professor of nutrition and dietetics at the University of Newcastle and co-director of the Food and Nutrition Research Program at the Hunter Medical Research Institute, pointed out the issue with undertaking further interventional research.

“The studies are observational, which means cause and effect cannot be proven and that the research evidence gets downgraded, compared to intervention studies,” Collins said. “The problem is that it is not ethical to do an intervention study lasting for many years where you feed people lots of UPF every day and wait for them to get sick and die.”

The researchers acknowledge that their review cannot establish causation; that would require further research, specifically randomized controlled trials. Nonetheless, they say that their rigorous and systematic approach to evaluating the credibility and quality of the analyses they looked at suggests that the result would withstand scrutiny.

The study was published in The British Medical Journal.

Source: Scimex/New Atlas