BRIEF REPORT: nutrition and weight loss information in a popular diet book: is it fact, fiction, or something in between?

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

OBJECTIVES

To describe and compare the references cited in popular books about diet and health between the USA and Japan.

DESIGN

Books were selected based on their best-seller rankings in the diet and health category of online bookstores. We identified references throughout all pages of the books and examined the number of references, reference format (identifiable or not) and presence of specific types of references, such as systematic reviews of human research. We compared the characteristics of references between the two countries and examined related factors to citation.

SETTING

Cross-sectional study.

PARTICIPANTS

Books (n 100 in each country).

RESULTS

Among 100 books from each country, sixty-five US and sixty-six Japanese books had references. Forty-five US books cited more than 100 references, against only five Japanese books. The number of books that cited systematic reviews of human research differed between the USA (n 49) and Japan (n 9). Additionally, the number of books that provided identifiable information for all references was significantly higher in the USA (n 63) than in Japan (n 42). Books whose first authors have licences of medical doctors were more likely to cite references than those without in both countries.

CONCLUSIONS

Two-thirds of books about diet and health cited references in both the USA and Japan, but Japanese books cited fewer references and were less likely to cite systematic reviews and provide identifiable references than US books. Further research into the scientific reliability of information in books about diet and health is warranted.

Popular fad diets: An evidence-based perspective

Despite the emergence of stronger nutritional science over the past two decades, fad diets remain highly popular. However, growing medical evidence has led to the endorsement of healthy eating patterns by medical societies. This thus allows fad diets to be compared to the emerging scientific evidence as to which diets promote or damage health. In this narrative review, the most popular current fad diets are critically analyzed, including low-fat diets, vegan and vegetarian diets, low-carbohydrate diets, ketogenic diets, Paleolithic diets, and intermittent fasting. Each of these diets has some scientific merit, but each has potential deficiencies relative to the findings of nutritional science. This article also presents the common themes that emerge among the dietary guidance of leading health organizations, such as the American Heart Association and the American College of Lifestyle Medicine. While there are important distinctions between dietary recommendations emanating from various medical societies, each recommends eating more unrefined, plant-based foods, while eating fewer highly processed foods and added sugars, and avoiding excessive calorie consumption as an important nutritional strategy for the prevention and management of chronic conditions and promotion of overall health.

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

OBJECTIVES

Kidney stone disease (KSD) has a strong association with diet metabolic syndrome. This review aims at exploring the lithogenic risk posed by the current most popular diets. Our approach was to search for the effect of each diet type on the major urinary risk factors, to try to draw conclusions regarding the association of a specific diet type and KSD.

METHODS

This systematic review searched for the available literature exploring the association between the existing popular fad diets and KSD. Articles in English, French and Spanish were included, without restriction of the search period with the final search done in August 2021.

RESULTS

Total number of studies and studies for each diet type was as follows: 22 articles for the low carbohydrate diet, 20 articles for high protein diets, 26 articles for vegetarian and vegan diets. There exists a substantial variability in different low carbohydrate and high protein diets, and considerable overlap between modern popular fad diets. High carbohydrate intake might increase urine uric acid, calcium and oxalate levels. High protein diets increase urine calcium and uric acid and lower urine pH and citrate. Consumption of fruits and vegetables increases the urinary volume and urinary citrate. In vegan diets, sufficient daily calcium intake is important to avoid possible secondary hyperoxaluria.

CONCLUSIONS

Few studies evaluated the direct relationship between modern fad diets and KSD. In general, the reduction of carbohydrate in the diet, and counterbalancing protein rich diets with sufficient intake of fruits and vegetables, seem to play a protective role against KSD formation. Maintaining sufficient calcium intake in vegan and vegetarian diets is important. Additional research is needed to directly evaluate the link between KSD and each diet type.

Lifestyle as Medicine: The Case for a True Health Initiative

The power of lifestyle as medicine was perceived thousands of years ago. There is now consistent and compelling science to support the important influence of lifestyle on health. Approximately 80% of chronic disease and premature death could be prevented by not smoking, being physically active, and adhering to a healthful dietary pattern. Cardiovascular disease, diabetes, stroke, dementia, and cancer are all influenced by lifestyle choices. Despite the ample evidence about what behaviors promote health, confusion still prevails among the general population. This is particularly true with regard to diet. Confusing nutrition messages from scientists, the media, the food industry, and other sources have made it all but impossible for any single authority to convey persuasively the fundamentals of healthful eating. The case is made here that a global coalition of diverse experts has the power to do what no individual can: clarify and popularize an understanding of the fundamentals of a health-promoting, sustainable pattern of diet and lifestyle, and rally the general public to their consistent support.