Diets high in ultra-processed foods are associated with an increased risk of more than 30 negative health outcomes, including mental health disorders, cardiovascular disease, Type 2 diabetes, obesity and early death, according to a new study published Wednesday in The British Medical Journal.

The latest study, which builds on decades of research connecting ultra-processed foods like prepackaged meals and sweetened drinks to poor health, sheds a staggering light on the need to improve our diets. Ultra-processed foods are estimated to account for up to 58% of total daily energy intake in some high income countries, according to the study researchers, and have become more prevalent in the diets of those living in low and middle income nations.

Researchers from the Deakin University School of Medicine in Australia and Johns Hopkins Bloomberg School of Public Health conducted an "umbrella review" of 45 meta-analyses on ultra-processed foods that involved nearly 10 million people.

"Highly suggestive evidence" found that higher ultra-processed food intake increased the risk of heart disease-related mortality by 66%, obesity by 55%, sleep disorders by 41%, Type 2 diabetes by 40% and depression by 22%. The risk of death from any cause increased by 21% among people who ate more ultra-processed foods.

Evidence for the associations between ultra-processed food consumption and asthma, gastrointestinal conditions and some cancers was "limited," the researchers said.

The study does not prove causation, meaning it's not known whether other factors led to people's greater risks of poor health outcomes. However, experts say that a balanced diet is key to feeling good and lowering the chances you develop major health issues as you age.

Here's what to know about ultra-processed foods.

What are ultra-processed foods?

Ultra-processed foods are ready-to-eat or ready-to-heat foods that have been changed from their natural forms via high-pressure shaping or chemical alteration to appear a certain way or have a longer shelf life. They are low in fiber, protein and vitamins, and high in sugar, fat and salt, often containing artificial colors and additives.

Ultra-processed foods include prepackaged meals, frozen pizza, breakfast cereals, sweetened drinks and desserts such as candy and ice cream.

What is an unprocessed or minimally processed food?

Unprocessed or minimally processed food exists in or close to its natural state. These can include fruits, vegetables, plain yogurt and coffee. Other minimally processed foods include items like jarred marinara sauce and roasted nuts.

'Processed' foods exist on a spectrum

"Processed" is not synonymous with "bad for you." But there are a few things to keep in mind when selecting what you plate for dinner.

"There are plenty of foods that are healthy and wholesome that have undergone some processing," Gena Hamshaw, a registered dietitian in New York City, tells USA TODAY. "I think when we start talking about ultra-processed foods, that often implies that they're in a form where they bear very little resemblance to their original whole food source."

"Think about a potato (versus) a french fry or potato chip," Samantha Cassetty, a registered dietitian nutritionist, tells USA TODAY. "Or a rotisserie chicken compared to a slice of chicken deli meat. A 100% whole grain cereal is going to be less processed than a sugary cereal made from refined flour."

How to avoid ultra-processed foods

When picking food items in the grocery store, you have two sources of information: a nutrition panel and an ingredient list, both of which are equally important. Paying attention to only one "is like buying a car on the internet without ever looking under the hood," Cassetty says.

The ingredients list is your go-to indicator of how processed a food might be. If an item is high in sodium, added sugars and saturated fat, it's processed, Cassetty says, even if there are no other preservatives or artificial sweeteners or colors.

Refined grains are another key indicator of processing. They're often found in white bread, crackers and cereal.

"I think there's some confusion about processed foods in the sense that we think it means to eliminate convenience," Cassetty says. "You can still have the convenience of packaged foods, but you just have to make different decisions when choosing them."

If you want to adopt more healthy eating habits, Hamshaw recommends starting small. "Choosing whole grains over refined grains more often is a great place to start." Then, consider opting for plant-based proteins like legumes, she says. 

Contributing: Morgan Hines