New study finds that diet soda, hot dogs, and other highly processed foods are even more unhealthy than you think

People who eat a lot of processed foods had a 10% higher risk of all-cause mortality.

Highly processed foods, such as bread, hot dogs, soda, doughnuts, chicken nuggets, and potato chips, are marked with a red downward arrow.

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Nobody said highly processed foods were good for your health, but a new study shows that regularly consuming foods like hot dogs, sugary soda, and refined grains may shorten your lifespan.

The study, presented at the Nutrition 2024 conference in June, followed more than 500,000 people and tracked their eating habits for 30 years. Researchers found that over the 23-year observation period, people who ate a lot of highly processed foods had a 10% higher risk of all-cause mortality than those who ate minimally processed foods. Study participants who ate more ultra-processed foods were more likely to have a higher body mass index (BMI) and lower overall diet quality, while some ultra-processed food fans were of normal weight but still had a higher risk of death.

The results have raised many eyebrows and questions about highly processed foods. And this goes like this:

What are highly processed foods? Foods are labeled as "highly processed" depending on where they fall on a classification system called the NOVA scale. Foods on the NOVA scale fall into four categories, including:

Raw and minimally processed foods. These are foods that are in their natural state or with minimal processing, like fresh fruits, vegetables, and milk, says Jessica Cording, R.D., R.D., a registered dietitian and author of The Little Book of Game-Changers: 50 Healthy Habits For Managing Stress & Anxiety.

Processed cooking ingredients. These foods are ingredients that have been minimally processed, like pressed, refined, crushed, or ground, like almond flour and olive oil. Processed foods. Processed foods have been altered from their natural state and often have added sugar, oil, salt and other substances, Cording says. This includes things like canned tuna and packaged vegetables.
Highly processed foods. Foods in this category are processed, but they still contain added ingredients like artificial colors and flavors, preservatives and other ingredients to maintain texture and shelf life.

A 2022 study published in the journal JAMA Neurology followed nearly 11,000 people and had them fill out questionnaires about the foods they ate and their calorie intake. At the end of the 10-year study, participants were assessed for cognitive performance. Researchers found that people who got more than 28% of their calories from highly processed foods had a higher risk of dementia. Another 2022 study published in the journal Neurology also found a link between highly processed foods and an increased risk of developing dementia.

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A study published in the British Medical Journal analyzed data from nearly 46,000 men and 160,000 women and found that men were 29% more likely to eat the most highly processed foods: higher risk of developing colon cancer. Another study, also published in the British Medical Journal, analyzed the diets of more than 22,000 people over a 14-year period and found that people who consumed a highly processed diet had a higher risk of developing chronic diseases, especially cardiovascular disease, and premature death.

Other studies have shown a link between sugary drinks and an increased risk of death. A 2019 study published in the journal Circulation found that women who consumed two sugary drinks daily had a 63% increased risk of premature death, while men had a 29% increased risk of premature death. Which highly processed foods are of most concern? Recent studies have found that certain highly processed foods are associated with a higher risk of death than others. This includes:

Diet soda
Sweet soda

Other studies have found that sauces, spreads, condiments, and convenience foods may also increase the risk of serious health complications from highly processed foods.

Nutritionists say you don't need to avoid these foods completely
The study's researchers emphasized that not all highly processed foods are bad, noting that some nutritious foods, such as unsweetened applesauce, ultrafiltered milk, liquid egg whites, and some types of raisins and canned tomatoes, are highly processed. They realized that quality matters.

Argentina, Colombia and Mexico have added "tobacco-esque" warnings to highly processed foods, but should the U.S. follow suit? If you're currently eating a lot of highly processed foods, Cording recommends focusing on adding more nutritious foods like fruits, vegetables and whole foods to "weed out" products that may be less nutritious. Goos agrees: "Instead of worrying about eating highly processed foods, focus your energy on making sure your daily meals include plenty of nutritious foods like fruits, vegetables, nuts and seeds, legumes, and 100% whole grains."

But Cording also stresses the importance of "making room for indulgences over time" while still eating healthily overall. "If you like certain highly processed foods and the majority of your diet consists of nutritious foods, there may be room for them."