According to new research, eating a diet high in protein could be as dangerous to your health as smoking 20 a day.

The University of Southern California, who conducted the research, defined a high protein diet as being at least 20% of a person’s daily calories. The results showed that those under the age of 65 who consumed this amount of animal protein had an increased risk of developing cancer.

Study author Dr Valter Longo, Professor of Biogerontology at the USC Davis School of Gerontology said: “High levels of protein can be as bad for you as smoking. People should understand the distinction and be able to make the decision about what they eat.”

Red meat, milk, and cheese are reportedly the most harmful but fortunately, there was no evidence to suggest fish protein has any harmful effect.

Dr Longo added:  “Some proteins are better for you than others, for example plant-based proteins like beans. Vegans seem to do better in studies than those who eat animal based proteins. Red meat always comes out top as the worst and that’s probably due to its other components.”

Unfortunately, the results will put a shadow over the benefits of high-protein diets like the Paleo diet.