Consumption of processed meat and unprocessed red meat is associated with a higher type 2 diabetes risk across populations, an analysis of data from 1.97 million participants, published in the journal The Lancet Diabetes and Endocrinology, has found.

Global meat production has increased rapidly in recent decades and meat consumption exceeds dietary guidelines in many countries. Earlier research indicated that higher intakes of processed meat and unprocessed red meat are associated with an elevated risk of type 2 diabetes, but the results have been variable and not conclusive.

Poultry such as chicken, turkey, or duck is often considered to be an alternative to processed meat or unprocessed red meat, but fewer studies have examined the association between poultry consumption and type 2 diabetes. To determine the association between consumption of processed meat, unprocessed red meat and poultry and type 2 diabetes, the team led by researchers at the University of Cambridge used the global InterConnect project to analyse data from 31 study cohorts in 20 countries. Their extensive analysis took into account factors such as age, gender, health-related behaviours, energy intake and body mass index.

The researchers found that the habitual consumption of 50 grams of processed meat a day —equivalent to 2 slices of ham — is associated with a 15% higher risk of developing type 2 diabetes in the next 10 years. The consumption of 100 grams of unprocessed red meat a day — equivalent to a small steak — was associated with a 10% higher risk of type 2 diabetes. Habitual consumption of 100 grams of poultry a day was associated with an 8% higher risk, but when further analyses were conducted to test the findings under different scenarios the association for poultry consumption became weaker, whereas the associations with type 2 diabetes for each of processed meat and unprocessed meat persisted.

“These findings highlight the importance of reducing meat consumption for public health and should inform dietary guidelines,” the authors write.