Bacon lovers be warned. New research says that red meat, particularly the processed kind, is linked with an increased risk of developing type 2 diabetes.

The study found that the daily consumption of a 100-gram serving of unprocessed meat, which is about the size of a deck of cards, increased the risk of developing type 2 diabetes by 19 per cent. The researchers, from Harvard School of Public Health, also found that consuming a daily 50-gram serving of processed meat, such as one hot dog or sausage or two slices of bacon, increased the risk of developing type 2 diabetes by 51 per cent.

The research included data from questionnaires completed by more than 37,000 men in the Health Professionals Follow-Up Study, more than 79,000 women in the Nurses' Health Study I and more than 87,000 women in the Nurses' Health Study II. The researchers combined that data with information from previous studies that included more than 440,000 participants.

The researchers reached their conclusions after adjusting for age, body mass index and other lifestyle and dietary factors.

"Clearly, the results from this study have huge public health implications given the rising type 2 diabetes epidemic and increasing consumption of red meats worldwide," senior study author Frank Hu, a professor of nutrition and epidemiology at the Harvard School of Public Health, said in a statement. "The good news is that such troubling risk factors can be offset by swapping red meat for a healthier protein."

Those healthier proteins include nuts, beans, fish, whole grains and low-fat dairy products.

According to the study, for an individual who eats one serving of red meat daily:

• substituting one serving of nuts per day is linked with a 21 per cent lower risk of type 2 diabetes.
• substituting low-fat dairy is linked with a 17 per cent lower risk.
• substituting whole grains is linked with a 23 per cent lower risk.

The study will be published in the American Journal of Clinical Nutrition.

It is estimated that nearly 350 million people around the world have type 2 diabetes, and many cases are linked primarily to obesity, lack of physical activity and an unhealthy diet.

Health Canada says type 2 diabetes is one of the fastest growing diseases in Canada, with more than 60,000 cases diagnosed annually.

While previous studies have confirmed a link between processed red meats and an increased risk of developing type 2 diabetes, research has been less clear about the association between unprocessed meats and the disease. This latest study is the largest of its kind to study the issue, for both its sample size and for taking into account both processed and unprocessed meats.

It is also one of the first to find a link between alternative protein sources and a lower risk of type 2 diabetes.

The researchers point out that dietary guidelines often put red meat in the same protein category as fish, nuts and beans, which suggests that they are equally healthy choices.

But they say their findings should caution meat lovers against over-indulging.