Global and local diet popularity rankings, their secular trends, and seasonal variation in Google Trends data

OBJECTIVES

The Internet has become the main source of health-related information including nutrition. The aim of this study was to rank the most popular diets among Google users globally and regionally in addition to secular and seasonal trends in the years 2004 to 2019.

METHODS

We used Google Trends (GT) to identify and analyze course over time and regional interest of 47 topics related to diets. We analyzed secular trends using the Seasonal Mann-Kendall test and seasonal variation using time-series decomposition. The topic "Mediterranean diet" (MedD) was used as a benchmark. We calculated the interest of all topics in proportion to the relative search volume (RSV) of MedD.

RESULTS

Globally, Google users were particularly interested in veganism (19.54 times higher than MedD), vegetarianism (15.09 times higher than MedD), and gluten-free diet (11.11 times higher than MedD). Veganism was the most frequently searched diet type in 23 countries followed by vegetarianism (14), ketogenic diet (7), and low-carbohydrate diet (7). Whereas an increase of RSV over time was observed for 23 diets, a decrease was noted for 20. The most dynamic increase was found for FODMAP (6.12 RSV/year), gluten-free diet (5.95 RSV/year), and raw veganism (5.72 RSV/year). Sharp declines concerned negative-calorie food (-4.34 RSV/year), macrobiotic diet (-3.89 RSV/year), and cabbage soup diet (-3.50 RSV/year). The interest in most diets falls in December but peaks in January.

CONCLUSION

Veganism, vegetarianism, and gluten-free diet attract the largest public interest globally. Both secular trends and seasonal variation shape the ever-changing landscape of diet popularity. GT holds promise as a valuable tool in local and international nutrition research.

Historical Developments and Paradigm Shifts in Public Health Nutrition Science, Guidance and Policy Actions: A Narrative Review

Public health nutrition (PHN) seeks to protect and promote the nutrition-related health and wellbeing of populations. PHN science is dynamic and has evolved over time, helping to inform our understanding of the changing nature, scope, causes and solutions to PHN problems. This scientific basis has informed nutrition guidance and policy. Using a narrative synthesis method and guided by Kuhn's theory on the structure of scientific revolutions, this paper reviews the historical development of PHN, aiming to understand the emergence of major scientific paradigms, paradigm shifts and evidence-informed guidance and policy. We propose that the development of PHN is characterized by the successive layering of paradigms resulting from interactions between science, social change and policy-making. Four eras of PHN are evident: the foundation, nutrient deficiency, dietary excess and imbalances, and environmental sustainability (ES). Dominant paradigms have been communicated through nutrient reference standards, dietary goals and dietary guidelines. Transitions from one era to the next indicated new ways of thinking about PHN, amounting to a paradigm shift. The bidirectional relationship between nutrition and ES is the latest challenge confronting PHN. Investigating PHN paradigm transitions reveals how we have arrived at current guidance and policies, and how PHN might progress into the future.