High protein diets such as the Paleo diet have become very popular, but although fans of these diets swear that they are healthy and great for losing weight and staying fit, doctors warn that they can be dangerous.

Studies show that high protein diets can be helpful for the elderly but can actually shorten the lifespan of middle aged men and women. Researchers have found that people who are over 60 and eating a high protein diet are 60% less likely to die of cancer and 28% less likely to die of any cause than those whose protein intake is lower.

While the benefits of high protein diets are obvious in the elderly, young adults and middle aged people who have a high protein intake from certain food may be at risk for developing cancer and some doctors even claim eating a high protein diet is the equivalent of smoking 20 cigarettes a day. Protein itself is not necessarily the problem, but more so the source of the protein. Red meat for example, is high in protein, but not the best option.

“High levels of protein can be can be as bad for you as smoking. People should understand the distinction and be able to make the decision about what they eat. 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. But the good news is that there is no evidence that fish is bad for you. So fish plus vegetables is really the best group of proteins,” said Dr Longo, Professor of Biogerontology at the USC Davis School of Gerontology.

Protein levels control the growth hormone IGF-I, which helps bodies grow but high levels of which have been linked to cancer. While the elderly are in need of higher IGF-I levels, the hormone can build up over time in a younger or middle aged person, and lead to cancer and other health problems.

If you are considering a high protein diet, you may want to reconsider. If you do decide to consume large amounts of protein, make sure it comes from a variety of good sources including fish, vegetables and legumes.

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