The Truth About Red Meat & Cancer Risk with USDA Scientist Dr. David Klurfeld

Clerfeld’s mentor, David Kuchevsky, drilled into him: 'never change what you do based on one study.' Clerfeld extends that to today’s media environment, where a single association study gets amplified as the final word. He explains that most controlled feeding studies are 'efficacy' trials – they work under tightly controlled conditions but may have no connection to your lifestyle. Even if a study is well-designed, a second and third examination is needed. He points to the Women’s Health Initiative, a $750 million randomized trial of low-fat diet in 50,000 women that found no benefit for cancer or heart disease, yet its lesson is still ignored by guidelines that cling to low-fat dogma.

Clerfeld recalls that Kuchevsky would advocate moderation and variety 'no matter who he was talking to,' even when the entire world was pushing low-fat. Forty years later, Clerfeld sees the same pendulum swings – low-fat, low-carb, plant-only – and believes the best defense is a varied diet that includes animal-source foods for their unique nutrient packages. He cautions against moralizing food choices based on environmental claims, pointing out that the lifecycle analysis data for different foods are not as solid as advocates imply, and that transportation to the grocery store has a bigger environmental footprint than food production.