Why did we change our dietary advice, and what did we change it to

For decades, the medical message was simple: eat less, move more, and follow the calorie formula. When that approach produced limited and temporary results, official dietary advice evolved—first toward low-fat, higher-carbohydrate eating, and later toward a wider range of patterns. Yet obesity rates continued to rise, and many patients still found lasting weight loss difficult.

Why Did We Change Our Dietary Advice, and What Did We Change It To? examines the historical and scientific reasons behind these shifts. Written by Dr Samir Contractor, a laparoscopic and bariatric surgeon, the book explores how calorie theory, low-fat guidelines, and later recommendations developed, what evidence drove the changes, and where the advice still falls short when measured against human physiology, metabolic adaptation, and real-world outcomes.

This is a practical, physiology-informed guide for anyone who wants to understand not just what the advice became, but why it changed—and what that means for more effective approaches today.