A new meta-analysis from the University of Washington suggests that no amount of processed food is safe to consume, challenging the notion that small quantities pose no significant risk. Researchers analyzed 77 different studies to gauge the link between certain amounts of these foods and common chronic diseases. Lead study author Demewoz Haile, a research scientist at the Institute for Health Metrics and Evaluation at the University of Washington, stated that habitual consumption of even small amounts of processed meat, sugary drinks, and trans fatty acids is linked to increased risk of developing type 2 diabetes, ischemic heart disease, and colorectal cancer.
The study highlights the dangers of processed meats, noting that as little as 0.6 to 57 grams per day was linked to an 11% greater likelihood of developing type 2 diabetes. Consuming between 0.78 and 55 grams per day was associated with a 7% increase in colorectal cancer risk, according to the findings. One hot dog, made up almost entirely of processed meat, is approximately 50 grams, adding context to the study’s conclusions.
The researchers also examined sugar-sweetened beverages, finding that drinking between 1.5 and 390 grams per day could raise type 2 diabetes risk by 8%. Additionally, consuming between 0 and 365 grams of these beverages could increase the risk of ischemic heart disease by 2%. Trans fatty acids were also analyzed, with consumption levels of 0.25% to 2.56% of daily energy intake linked to a 3% greater risk of ischemic heart disease.
While the study’s conclusions are clear, the researchers acknowledged limitations, including the challenges in accurately assessing long-term dietary intake and the potential for measurement errors. The study also noted that some included studies only assessed consumption at the start of the study, which may not reflect future dietary habits. Additionally, the range of health outcomes examined for each dietary risk factor was limited, potentially leading to an underestimation of the total health impact.
Critics, such as Dr. Nick Norwitz, a clinical researcher and metabolic health educator, pointed out that while the study shows a relatively consistent association between higher processed meat intake and worse health outcomes, it does not establish causality. Norwitz emphasized that the quality of evidence was graded as ‘weak’ and suggested that lumping together various food items within a single category may obscure the nuanced biological effects of different food processing methods.
Industry representatives, like the American Association of Meat Processors, have responded by seeking clarification on the study’s methodology and definitions, particularly regarding the classification of processed meat and the balance between potential risks and the proven benefits of nutrients and protein found in meat.