For decades, the guidance has been nearly universal: choose low-fat dairy, avoid the full-fat version, and protect your heart and waistline accordingly. A new study published in The Journal of Nutrition now invites a quieter, more careful question — not whether that advice was wrong, but whether it was too simple. Seventy-four overweight adults ate full-fat dairy freely for twelve weeks and emerged without the weight gain, worsening cholesterol, or metabolic harm that conventional wisdom had long predicted, suggesting that some of nutrition science's most familiar certainties may deserve a sec