Brief report: Nutrition and weight loss information in a popular diet book: Is it fact, fiction, or something in between?

Abstract

BACKGROUND/OBJECTIVE: Diet books dominate the New York Times Advice Best Seller list and consumers cite such books as an important source of nutrition information. However, the scientific support for nutrition claims presented as fact (nutrition facts) in diet books is not known. DESIGN/MEASUREMENTS: We assessed the quality of nutrition facts in the best‐selling South Beach Diet using support in peer‐reviewed literature as a measure of quality. We performed structured literature searches on nutrition facts located in the books' text, and then assigned each fact to 1 of 4 categories (1) fact supported, (2) fact not supported, (3) fact both supported and not supported, and (4) no related papers. A panel of expert reviewers adjudicated the findings. RESULTS: Forty‐two nutrition facts were included. Fourteen (33%) facts were supported, 7 (17%) were not supported, 18 (43%) were both supported and not supported, and 3 (7%) had no related papers, including the fact that the diet had been “scientifically studied and proven effective.” CONCLUSIONS: Consumers obtain nutrition information from diet books. We found that over 67% of nutrition facts in a best‐seller diet book may not be supported in the peer‐reviewed literature. These findings have important implications for educating consumers about nutrition information sources.

Are popular books about diet and health written based on scientific evidence? A comparison of citations between the USA and Japan

“…Another previous study evaluated nutrition facts presented in a single best-selling book by searching peer-reviewed literature that would or would not support the facts (41) . The study found that only one-third of the nutrition facts was supported by peer-reviewed literature (41) .…”

“…Another previous study evaluated nutrition facts presented in a single best-selling book by searching peer-reviewed literature that would or would not support the facts (41) . The study found that only one-third of the nutrition facts was supported by peer-reviewed literature (41) . Although this previous and our present study differ in focus and the number of books examined, both suggest that nutritional information provided in popular US books is not necessarily based on scientific evidence.…”

The Relationship between Modern Fad Diets and Kidney Stone Disease: A Systematic Review of Literature

“…The Zone diet includes a mild reduction in carbohydrate intake to 40% of total macronutrient intake, and a mild increase of protein and fat intake to 30% each of the total nutritional intake per day. The South Beach diet, a more recent approach, is a fiber-rich diet that promotes intake of complex carbs, or so-called good carbs, from various sources such as fruits, vegetables, whole grains, and beans, while avoiding simple or "bad" carbs, represented by sugar and industrial syrups and sweeteners [10,[16][17][18]. An extreme modification of a LC diet, the ketogenic or "keto" diet, induces a nutritional ketosis and thus production of ketone bodies from fat tissue in the body, by increasing energy intake from fat, and significant restriction of carbohydrate intake to 20-50 g per day and subsequent glycogen storages' depletion.…”

Lifestyle as Medicine: The Case for a True Health Initiative

“…These differences are what receive the overwhelming preponderance of attention in diet books, the media, and from the food industry, resulting in conflicting messages. 47,48 The US weight loss market in 2014 was valued at US$59.8 billion, a portion of which is derived from diet book sales. 49 Thousands of diet books are published by scientists and researchers every year, each with the potential to exert influence over public perceptions.…”

“…These differences are what receive the overwhelming preponderance of attention in diet books, the media, and from the food industry, resulting in conflicting messages. 47,48…”