The papers analyzed past studies on red and processed meat and generally corroborated the links to cancers, heart disease and other bad health outcomes. But they said the chance of any benefit from eating less of them appeared small or negligible.
For every 1,000 people, for instance, cutting back on red meat by three servings a week was linked to seven fewer deaths from cancer. For some other health measures, like strokes, the difference was smaller or nonexistent.
What’s more, the researchers said there’s little certainty meat was the reason for the differences.
Uncertainty is common in nutrition research. Many studies about food and health are based on links researchers make between people’s health and what they say they eat. But that doesn’t prove one causes the other. If a thin person loves cereal and eats it nearly every day, for instance, that doesn’t mean cereal is the reason they’re thin.
Health experts who defend advice to cut back meat say the researchers were applying an unreasonable standard — evaluating the strength of the meat studies with a method intended for medical studies, where a specific dose of drug can be tested under controlled conditions.
With nutrition, they say it’s impossible to conduct studies where people’s diets and lifestyles are controlled and monitored over long periods. They say the statistical signals they see in nutrition studies are meaningful, and that people should be given guidance on the best available data.
THE PERSON VS. THE POPULATION
If it’s true that there would be seven fewer cancer deaths for every 1,000 people who cut back on red meat, then it is also true that 993 of those people would not see that benefit even if they ate fewer burgers.