Dear Editor, Obesity is a chronic systemic condition that affects multiple organs and markedly raises the risk of metabolic, cardiovascular, hepatic, neurological, respiratory, and oncologic disorders1–4. It is estimated that more than one billion people will have obesity by 20305. Obesity is caused by an imbalance between energy intake and expenditure6. Diet-induced obesity has become an epidemic7. It is solely attributed to increased caloric intake from fats8. Bibliometric analysis is a quantitative approach based on statistical sampling that offers a systematic means to assess research trends, productivity, and impact9. This study addresses the lack of a comprehensive assessment of global high-fat diet (HFD) and obesity research worldwide. It highlights a shift toward microbiota-centered, multi-omics frameworks by combining bibliometric, clustering, and thematic analyses. These insights elucidate the mechanisms underlying diet-induced metabolic risk and provide therapeutically meaningful recommendations for metabolic assessment and perioperative care in obesity. With the document types confined to articles and reviews and the language limited to English, the Web of Science Core Collection was searched for studies published between 1 January 2000 and 20 October 2025. A total of 3864 articles were retrieved. A third reviewer mediated disagreements between the two independent reviewers who screened and assessed the article quality. To prevent database update bias, all searches and exports were finished on 20 October 2025. CiteSpace, VOSviewer, and Bibliometrix were used to map collaborations and trends. All data were publicly accessible and did not require ethical approval (Supplemental Digital Content Figure 1, available at: https://links.lww.com/JS9/H196 shows the research design; Supplemental Digital Content Figure 2A, available at: https://links.lww.com/JS9/H196 shows the data overview). Publications on HFD and obesity increased steadily between 2000 and 2025 (Supplemental Digital Content Figure 2B, available at: https://links.lww.com/JS9/H196, Supplemental Digital Content Data 1, available at: https://links.lww.com/JS9/H197). Supported by robust global collaboration, China currently leads the world in output, followed by South Korea and the USA (Supplemental Digital Content Data 2, available at: https://links.lww.com/JS9/H198). Publications have increased gradually since 2000, with a rapid acceleration after 2010. Asian universities, particularly the China Agricultural University, Zhejiang University, and Kyung Hee University, have spearheaded recent expansion, although early research was primarily driven by Westerners. Growing clinical concern over diet-induced metabolic disorders is reflected in post-2020 rises (Fig. 1A, Fig. 1B, Supplemental Digital Content Data 3, available at: https://links.lww.com/JS9/H199). Figure 1.: (A) Country output showing proportions of single (SCP) and multiple-country publications (MCP). (B) Annual publication trends of leading institutions. (C) Terminology network analysis. (D) Keyword heatmap showing temporal shifts between 2000 and 2025. (E) Co-citation clusters. (F) Timeline view of major co-citation clusters. The term co-occurrence map highlights three clusters (Fig. 1C): experimental and phenotypic terms (blue), mechanistic metabolic-microbiota pathways (green), and molecular control, including gene expression and lipid metabolism (red). Obesity, inflammation, insulin resistance, metabolism, and HFD are among the key terms that have steadily increased in frequency from 2000 to 2025, as shown by the heatmap. After 2015, “gut microbiota” and “oxidative stress” accelerated sharply, reflecting a shift toward mechanistic and microbiota-centered research (Fig. 1D, Supplemental Digital Content Data 4, available at: https://links.lww.com/JS9/H200). The CiteSpace clustering and timeline analyses show 10 major co-citation clusters in HFD and obesity research (Fig. 1E, Fig. 1F). “Gut microbiota” is the largest and most central cluster, and it is strongly associated with inflammation, insulin resistance, and overt obesity. Early research (2000–2010) focused on adipocyte biology and metabolic impairment, whereas after 2015, studies shifted toward metagenomics, microbial regulation, and obesity-associated inflammation. Recent clusters, particularly gut microbiota, fat browning, and microbial interventions, show dense post-2020 activity. This indicates rapid expansion and a field that is increasingly focusing on host-microbe interactions and mechanistic metabolic pathways. The thematic map shows four primary domains in HFD and obesity research (Supplemental Digital Content Figure 3A, available at: https://links.lww.com/JS9/H196). Motor themes include weight, adiposity, and metabolic regulation, whereas niche themes include nonalcoholic fatty liver disease and obesity-associated metabolic disorders. Emerging or declining themes emphasize a diminished focus on natural compounds, and basic themes highlight fundamental animal-model research. The evolution map shows an early emphasis on gene expression and metabolic syndrome (Supplemental Digital Content Figure 3B, available at: https://links.lww.com/JS9/H196), a shift toward gut microbiota, oxidative stress, and insulin resistance between 2010 and 2020, and a recent shift toward multi-omics, short-chain fatty acids, and pharmacological interventions, such as semaglutide, between 2020 and 2025. This analysis demonstrates the rapid expansion of global research on obesity caused by HFD, which has been increasingly driven by Asian institutions and strengthened international collaborations. Keywords, clustering, and thematic trends consistently demonstrate a transition from phenotypic and metabolic findings to microbiota-centered, multi-omics, and mechanistic frameworks. The predominance of gut microbiota, inflammation, insulin resistance, and emerging pharmacological targets, such as semaglutide, highlights a developing topic with direct clinical relevance. These developments offer a more robust molecular foundation for enhancing metabolic risk assessment, directing dietary approaches, and influencing perioperative care for patients with diet-induced obesity.
Zheng et al. (Fri,) studied this question.