German researchers analyzed 37 published studies assessing the benefits of switching from red and processed meats, poultry, fish, eggs and dairy products to plant-based foods such as legumes, nuts, whole grains, oils, fruits and vegetables.
They found that rates of cardiovascular disease and type 2 diabetes were significantly reduced during the study period, as was the risk of death from any cause, especially when red and processed meats were replaced with plant-based foods.
Sabrina Schlesinger, PhD, of the German Diabetes Center in Düsseldorf and senior author of the study, said:
“This evidence highlights the potential benefits of switching from an animal-based diet (including red and processed meats, eggs, dairy, poultry and butter) to plant-based foods (such as nuts, legumes, whole grains and olive oil).
Replacing 50 grams of processed meat per day with nuts or legumes reduces the risk of cardiovascular disease by approximately 25 percent. Meanwhile, replacing 1 egg with 25 grams of nuts per day reduced the risk by 17%. But there is no clear evidence that replacing poultry or fish with nuts or legumes reduces cardiovascular disease.
Similar benefits were seen for type 2 diabetes and for all causes of death recorded in the analysis study. The authors calculated that replacing 50 grams of processed meat per day with up to 28 grams of nuts, or replacing eggs per day with 30 grams of whole grains or 10 grams of nuts, would reduce the incidence of type 2 diabetes by about 20 percent.
Substituting processed meats (usually red meats such as ham, bacon, sausage, or hot dogs) is associated with the most significant health benefits. According to BMC Medicine, swapping 50 grams of processed meat for 28-50 grams of nuts per day was associated with a 21% lower risk of all-cause death in the studies evaluated.
The study didn’t delve into the reasons for the observed health benefits, but meat is often high in saturated fatty acids, which are thought to increase the risk of cardiovascular disease and type 2 diabetes. Processed meats may also contain high amounts of sodium, nitrates, and nitrites. Plant-based foods, on the other hand, are rich in essential nutrients such as dietary fiber, vitamins and minerals, antioxidants, and phytochemicals that suppress inflammation.
Professor Nita Forouhi, an expert in nutrition, diabetes and obesity at the MRC Epidemiology Unit at the University of Cambridge, said the study’s most compelling finding was the replacement of processed and unprocessed red meat with plant-based foods.
One drawback is that the study did not differentiate between different types of dairy products. The study also did not explore the benefits of replacing red and processed meat with other animal foods such as fish, poultry and eggs.
Professor Forouhi said: “Researchers are calling for further, higher quality studies. However, while we wait, it would be prudent to focus specifically on reducing intake of red and processed meat because of their health and environmental consequences. The potential adverse effects are the greatest.”