No Amount of Processed Meat is ‘Safe’ for Health, Finds Major Review

Even small amounts of processed meats like hot dogs and bacon are associated with the risk of type 2 diabetes, heart disease, and cancer, a new study has found.

While Americans celebrated overconsumption at Nathan’s Famous’s annual hot dog eating contest on July 4, scientists warned in a new review that there’s no safe amount of processed meat to eat.

It’s no secret that reconstituted meat products like sausages, hot dogs and bacon are bad for you – the WHO classed them as carcinogenic a decade ago. But its evaluation did not provide a safe limit for consumption.

Now, researchers at the University of Washington have concluded that there isn’t one, having reviewed over 70 studies with millions of participants. They found that processed meat, sugary drinks and trans fatty acids are all associated with a greater risk of ischemic heart disease, colorectal cancer, and type 2 diabetes.

That said, the impact of processed meat is the most striking, with even small amounts linked to increased health risks.

“The monotonic increases in health risk with increased consumption of processed meat suggest that there is not a ‘safe’ amount of processed meat consumption with respect to diabetes or colorectal cancer risk,” the study, published in the Nature Medicine journal, states.

How processed meat raises the risk of life-threatening diseases

The research found that consuming sugar-sweetened beverages was associated with an 8% increase in type 2 diabetes risk and a 2% rise in heart disease risk, while trans fats were connected to a 3% increase in the latter.

However, the health implications of processed meat dwarfed were much broader. Relative to zero processed meat intake, eating the equivalent of one hot dog a day increases the risk of developing type 2 diabetes by 11%, colorectal cancer by 7%, and ischemic heart disease by 2%.

The research found that the excessive amounts of sodium, nitrates and chemical preservatives in processed meat can harm cell DNA, create cancerous tumours, and damage pancreatic cells (which inhibits insulin production, leading to high blood glucose levels and subsequently type 2 diabetes). The high saturated fat content, meanwhile, has been linked to increased inflammation in the heart.

“When we look at the actual data there, it’s really remarkably consistent and remarkably strong,” said Mingyang Song, associate professor of clinical epidemiology and nutrition at the Harvard TH Chan School of Public Health, who was not involved in the study. “And even in the lower dose of consumption, we can still see an increased risk of disease.”

For example, studies analysed in the review suggested that people who ate 50g of processed meat a day (the same as two slices of ham) had a 30% higher chance of developing type 2 diabetes and 26% greater risk of colorectal cancer.

It’s important to note that the researchers used studies that relied on self-reported dietary consumption (which aren’t always fully accurate), and the associations don’t prove a direct cause-and-effect relationship.

At the same time, the study has strengths too. It uses a burden-of-proof method, a newer kind of meta-analysis that accounts for not just the number of links between diets and disease, but also how strong they are. The results of this method are conservative, so they likely underestimate the true health dangers of processed meat.

Processed meat under the spotlight in dietary guideline update

Nutrition and medical experts have long warned of the health risks of processed meat consumption, and this mega-review is the latest to add to calls for people to cut back on these products.

The review comes as the US government mulls its next dietary guidelines. Scientists have officially recommended a reduction in red and processed meat consumption while highlighting the benefits of plant proteins.

According to the Centers for Disease Control and Prevention (CDC), over 75 million American adults eat processed fast food every day. In addition, research shows that 63-74% of them consume red and processed meat on any given day.

A tenth of them have diabetes (mostly type 2), which kills more than 100,000 Americans every year. Cardiovascular disease is the main cause of mortality in the US, leading to the death of one person every 33 seconds. And colorectal cancer is set to cause over 50,000 deaths this year, with over 150,000 new cases of the condition estimated in 2025.

While ultra-processed foods (UPFs) have been in the spotlight, a commentary in the same journal as the study noted that they can be important for food security. Still, processed meat has often been bundled in the same group as plant-based alternatives – even as research shows the latter can support better cholesterol levels, improved diet quality, and modest weight loss than conventional processed meat.

Macronutrient profiles show that plant-based meat only meets three out of eight criteria used to classify UPFs, whereas processed meat ticks seven of them. “The best available evidence… suggests that replacing processed meat with plant-based versions could have medically relevant health benefits, most notably reductions in LDL cholesterol,” the report said.