Eating just two servings of red meat per week may increase the risk of developing type 2 diabetes, new research suggests.

It also found that replacing red meat with plant-based protein sources, such as nuts and legumes, may reduce the chances of developing the condition.

Limiting red meat consumption to about one serving per week would be reasonable for people wishing to optimise their health, the researchers suggest.

Previous studies have indicated a link between red meat consumption and type 2 diabetes risk, and researchers say this study adds a greater level of certainty about the association.

It analysed a large number of type 2 diabetes cases among people being followed for an extended period of years.

First author Xiao Gu, postdoctoral research fellow in the department of nutrition at Harvard T H Chan School of Public Health in the US, said: "Our findings strongly support dietary guidelines that recommend limiting the consumption of red meat, and this applies to both processed and unprocessed red meat."

In the study, published in the American Journal of Clinical Nutrition, researchers looked at health data from 216,695 people from the Nurses' Health Study (NHS), NHS II, and Health Professionals Follow-up Study (HPFS) in the US.

People were asked to complete questionnaires about their diet every two to four years, for up to 36 years.

During this time, more than 22,000 of them developed type 2 diabetes.

According to the findings, eating red meat, including processed and unprocessed red meat, was strongly associated with increased risk of type 2 diabetes.

Those who ate the most red meat had a 62 per cent higher risk of developing the condition compared to those who ate the least.

The research suggests that every additional daily serving of processed red meat was associated with a 46 per cent greater chance of developing type 2 diabetes.

Every additional daily serving of unprocessed red meat was associated with a 24 per cent greater risk, the study found.

Estimating the potential effects of replacing one daily serving of red meat for another protein source, researchers found that substituting a serving of nuts and legumes was associated with a 30 per cent lower risk of type 2 diabetes. Substituting a serving of dairy products was linked to a 22 per cent lower risk.

Senior author Walter Willett, professor of epidemiology and nutrition, said: "Given our findings and previous work by others, a limit of about one serving per week of red meat would be reasonable for people wishing to optimise their health and wellbeing."

According to the scientists, swapping red meat for healthy plant protein sources would help reduce greenhouse gas emissions and tackle climate change, and provide other environmental benefits.