Burkitt and Trowell called their fiber hypothesis a “major modification” of Cleave’s ideas, but they never actually addressed the reasons why Cleave had identified refined carbohydrates as the problem to begin with: How to explain the absence of these chronic diseases in cultures whose traditional diets contained predominantly fat and protein and little or no plant foods and thus little or no fiber—the Masai and the Samburu, the Native Americans of the Great Plains, the Inuit? And why did chronic diseases begin appearing in these populations only with the availability of Western diets, if they weren’t eating copious fiber prior to this nutrition transition? Trowell did suggest, as Keys had, that the experience of these populations might be irrelevant to the rest of the world. “Special ethnic groups like the Eskimos,” he wrote, “adapted many millennia ago to special diets, which in other groups, not adapted to these diets, might induce disease.” Trowell spent three decades in Kenya and Uganda administering to the Masai and other nomadic tribes, Burkitt had spent two decades there, and yet that was the extent of the discussion.

Unlike the reaction to Cleave’s hypothesis, which garnered little attention even after Cleave testified to McGovern’s Select Committee, the media pounced on the fiber hypothesis almost immediately. After Trowell published a pair of articles on fiber and heart disease in The American Journal of Clinical Nutrition in 1972, Robert Rodale, a nationally syndicated columnist, wrote a series of articles on the research, touting fiber as the answer to heart disease and obesity. Rodale was president of Rodale Press and the Rodale Institute, both dedicated to furthering the cause of organic foods and chemical-and pesticide-free “regenerative” agriculture. Rodale saw Burkitt and Trowell’s fiber hypothesis as validation of the wisdom of organic foods and the agrarian lifestyle. “The natural fiber in whole processed foods may be instrumental in keeping cholesterol levels low and preventing the onset of heart disease,” he wrote.

Burkitt and Alec Walker followed up Trowell’s articles with an August 1974 review in The Journal of the American Medical Association discussing the causal chain from fiber to constipation and “changes in gastrointestinal behavior” to the entire spectrum of Western diseases. The Washington Post wrote up the JAMA article on the day of its release, calling fiber “the tonic for our time.” That December, Reader’s Digest published an article on Burkitt and the fiber hypothesis; a year later, the magazine claimed that sales of fiber-rich products had more than doubled since the article. The breakfast-cereal industry, led by Kellogg and General Foods, immediately started pushing bran and fiber as inherent heart-healthy aspects of their products. In 1975, Burkitt and Trowell published a book, Refined Carbohydrate Foods and Disease.