A new study suggests that those who consume animal proteins are at a higher risk for death than those who do not. This is even true when those who do not ingest animal proteins are heavy drinkers and smokers. The good news here is that replacing animal proteins with plant proteins seems to significantly reduce the mortality risk.
The study was conducted at Harvard University and Massachusetts General Hospital in Boston where 130,000 healthcare professionals across the United States were followed over several decades. Half of those participating in the study were getting at least 14% of their protein from animal products.
At the end of the study, researchers stated that each 3% increase in calories of plant protein lowered the risk of death (in the study period) by 10%.
The report stated that those who were obese or heavy drinkers and ate large amounts of animal proteins were even more likely to die during the study.
Lead author of the study, Dr. Mingyang Song, stated:
“Plants are a better source than animal products. If people do have to choose among animal products, try to avoid processed red meat and choose fish or chicken instead.” 
He also added:
“Our findings have important public health implications. They can help refine the current dietary recommendations about protein intake and really get to the point that it is not only the amount but also the food sources of protein that are critical for long-term health.”
While the study did find that plant proteins are ideal, it was also found that those who lead a healthy lifestyle, regardless of their animal protein intake, were less likely to die during the study. Eating more plant protein for a healthy person, according to the study, doesn’t seem to lower their mortality risk.
Song notes that animal proteins alone may not be the cause of the higher mortality risk, but the type of animal protein consumed.
“Alternatively, it is possible that other components in the foods than protein per se may be the culprit. For example, processed red meat is high in sodium, nitrites and nitrates, which have all been linked to worse health outcomes.” 
Although the study cannot be considered conclusive, as it is observational, Song recommends attempting to replace some of your animal protein consumption with grains, legumes, nuts, and cereals for a healthier diet. And some plants!
 CBC Radio Canada