In the mid-1990s, Carlos Monteiro, a nutritional epidemiologist in Brazil, observed a troubling trend: a rapid increase in childhood obesity rates in his country.

To discern the cause, Monteiro and his team at the University of Sao Paulo scrutinized data on Brazilian household food purchasing patterns. They discovered a shift towards less sugar, salt, cooking oils, and staples like rice and beans, and an uptick in processed foods such as sodas, sausages, instant noodles, and packaged breads and cookies.

This led them to introduce a new term, “ultraprocessed foods” (UPFs), into scientific discourse. Subsequent research linked UPFs to weight gain in both Brazilian children and adults.

Since then, numerous studies have associated UPFs with various health issues, including heart disease, type 2 diabetes, obesity, gastrointestinal diseases, depression, and premature death.

However, questions remain about what UPFs are and how harmful they truly are. Here’s what experts have to say:

What Are Ultraprocessed Foods?

Monteiro and his colleagues developed the Nova food classification system, categorizing foods into four groups:

  1. Unprocessed or minimally processed foods: Includes fresh or frozen fruits and vegetables, meats, poultry, fish, eggs, milk, plain yogurt, rice, pasta, and herbs.
  2. Processed culinary ingredients: Such as cooking oils, butter, sugar, honey, vinegar, and salt.
  3. Processed foods: Comprising items from Group 1 combined with ingredients from Group 2 and preserved or modified using simple methods like canning or baking.
  4. Ultraprocessed foods: Made using industrial methods and containing additives like flavorings, colorings, or emulsifiers. Examples include sodas, chips, candies, processed meats, and boxed macaroni and cheese.

Are Ultraprocessed Foods Harmful?

Most research on UPFs relies on observational studies, associating their consumption with various health issues. However, causation remains unproven.

One clinical trial found that participants consuming UPFs gained weight and consumed more calories compared to when they consumed unprocessed foods. Yet, further research is needed to confirm these findings.

Why Might UPFs Be Harmful?

UPFs are often cheap, convenient, and palatable, potentially leading to overconsumption. They may also cause blood sugar spikes, inflammation, or disruptions to the gut microbiome.

What Should We Do About Ultraprocessed Foods?

Some countries, like Brazil, Mexico, Israel, and Canada, recommend limiting UPFs. However, strategies vary, from outright avoidance to moderation and emphasizing whole foods.

As research continues, the debate surrounding UPFs remains nuanced. While they are a significant food source, individuals are encouraged to prioritize minimally processed options and home-cooked meals when possible.