Excessive Middle Age Protein Intake as Harmful as Smoking

Two new studies find that low protein consumption may hold the way to a long and healthy life, at least until the oldest age range. They also emphasize the need to analyze not just calories when determining what constitutes a sound eating regimen, but where those calories are coming from; for example, whether protein is animal or plant-based.

An additional key discovery is that while a high-protein eating regimen may temporarily help individuals get more fit and boost muscle to fat ratios, it may actually hurt long-term health and decrease lifespan. Both studies are reported in the journal Cell Metabolism.

The first study was headed by Valter Longo, a professor at the University of Southern California, who demonstrated that high protein intake is linked to an elevated risk of cancer, diabetes, and death in middle-aged people, although this was not true for elderly individuals who saw benefits from moderate protein intake. Likewise, the impact is greatly diminished when the protein comes from plant sources.

In their study, Prof. Longo and partners analyzed information on over 6,800 American adults who participated in the National Health and Nutrition Examination Survey (NHANES) III, a US national study that evaluates health and eating habits.

Among their findings, they discovered that elderly individuals over the age of 50 who claimed they ate a high-protein diet were four times more likely to die from cancer or diabetes and twice as likely to die for any reason in the following 18 years. These impacts either lessened or vanished for individuals whose high-protein eating habits were primarily plant-based.

However, for those who were over the age of 65, there was almost an inverse effect – high protein consumption was linked to a 60% diminished risk of death from cancer and a 28% lower risk of dying for any reason, with similar results for moderate protein consumption.

In the second study, Prof.  Stephen Simpson, of the University of Sydney and his colleagues trialed the impacts of 25 separate eating methodologies on hundreds of mice to determine how differing types of proteins, fats and sugars influenced energy consumption, metabolic health, aging and lifespan.

They found that mice whose diets were high in protein and low in carbohydrates had diminished food intake and lower muscle to fat ratios, yet they also died prematurely and had worse cardiovascular health. The healthiest, longest living mice had diets that were high in sugars and low in protein – this was despite higher food intake and having larger muscle to fat ratios.

Prof. Simpson concludes, “”We have indicated expressly why it is that calories aren’t all the same – we have to take a look at where the calories hail from and how they interact. This examination has gigantic implications for what amount of food we consume, our muscle to fat ratios, our heart and metabolic health, and finally, the length of our lives.””

Written by Stuart Diamond