High-protein diet as deadly as smoking when it comes to cancer

The next time you're at your favourite Italian restaurant, you might want think twice about ordering the chicken Parmesan or chicken Alfredo.

A new study has found that a diet rich in animal protein (e.g. meat and cheese) is as dangerous as smoking when it comes to a person's risk of dying from cancer.

The study, published in Cell Metabolism, found that for those aged 50-65, eating a diet high in animal protein makes them four times more likely to die of cancer than someone eating a low-protein diet -- a mortality risk factor comparable to smoking.

However, after age 65, eating a high-protein diet has the opposite effect, as the extra protein can help sustain muscle mass and body weight.

"The majority of Americans are eating about twice as much proteins as they should, and it seems that the best change would be to lower the daily intake of all proteins but especially animal-derived proteins," says researcher Valter Longo from the University of Southern California. "But don't get extreme in cutting out protein. You can go from protected to malnourished very quickly."

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Researchers tracked 6,381 Americans between the ages of 50-65 for 18 years and monitored both their animal and plant protein consumption. A "high-protein" diet was defined as getting at least 20 per cent of calories from either type of protein and a "low-protein" diet included less than 10 per cent protein from either source.

The results showed that people with diets high in animal-based proteins were not just more likely to die from cancer, but also 75 per cent more likely to die prematurely due to any cause, including diabetes.

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The researchers note that the effects of premature death were not seen for high plant-based protein diets, which include legumes and nuts. And in fact, study participants with high plant protein diets had a lower risk of dying from cancer.

Most health agencies recommend a daily intake of protein based on a person's weight. The rule of thumb is to consume 0.8 grams of protein for every kilogram of body weight. Health Canada doesn't provide a recommended daily intake of protein because it is assumed that Canadians are getting more than enough protein in their diet.

What are your thoughts on the findings of this study? Do they surprise you in any manner?