Meat and cheese may kill you in middle age, study finds

The high-protein, low-carb prescription often encouraged for weight loss and blood sugar control could be a death sentence, according to a new
study published in Cell Metabolism.

In fact, consumption of animal proteins could be as dangerous to your health as smoking, the University of Southern California researchers found.

The study, which tracked a large sample of adults over two decades, suggests that a diet rich in meat and cheese during middle age increases your chances of dying from cancer four-fold. This type of diet was also linked to early death in general, as protein-lovers were more likely to die of any cause during the study period than their peers who ate low-protein diets.

Nutrition habits should change with age

The problem, say researchers, is that diet trends like Atkins or Paleo tend to focus on short-term results, but may not be healthy for people in the long term.

"There's a misconception that because we all eat, understanding nutrition is simple," said corresponding author Valter Longo, the Edna M. Jones Professor of Biogerontology at the USC Davis School of Gerontology and director of the USC Longevity Institute. "But the question is not whether a certain diet allows you to do well for three days, but can it help you survive to be 100?"

While the debate about how much protein is good for you has been a long-argued topic, the current study is one of the first to show a definitive correlation between high protein consumption and mortality rates. Moreover, the results suggest that dietary choices in adulthood may need to be tweaked while we age, as what's healthy for you at one age may be harmful at another.

A press release on the study elaborated:

Protein controls the growth hormone IGF-I, which helps our bodies grow but has been linked to cancer susceptibility. Levels of IGF-I drop off dramatically after age 65, leading to potential frailty and muscle loss. The study shows that while high protein intake during middle age is very harmful, it is protective for older adults: those over 65 who ate a moderate- or high-protein diet were less susceptible to disease.

Most eat too much animal protein

Longo noted that most Americans are eating about twice as much protein as necessary. A healthy dose of protein for a 130-pound person would be about 40-50 grams of protein per day, he explained, which corresponds to guidelines set forth by leading health agencies.

Plant-based proteins, furthermore, such as those from beans or legumes, don't seem to affect mortality or cancer risk. Adjusting carbohydrate or fat consumption, too, didn't change rates of cancer or death – suggesting that animal protein is the main culprit.

The researchers concluded that while cancer risk naturally increases as we age, dietary factors will play a large role in whether or not the condition develops beyond a certain point.

"Almost everyone is going to have a cancer cell or pre-cancer cell in them at some point," Longo said. "The question is: Does it progress? Turns out one of the major factors in determining if it does is protein intake."

Source: USC