Abstract
Restrictive diets, including whole-food diets (WFD) and animal-based (“carnivore”) diets (ABD), are increasingly promoted for rapid weight loss and improved health. However, evidence directly comparing the short-term physiological effects of such dietary patterns under similar energy and protein intake remains limited. PURPOSE: This single-subject case study compared the effects of a WFD and an ABD under matched energy and protein intake in a real-world setting. METHODS: A 37-year-old active male completed a 12-week protocol including 4 weeks of WFD (excluded processed foods while permitting Greek yogurt, nut butters, rice, and quinoa; added sugars, wheat, other grains, and most dairy products were excluded), a 4-week washout period (2 weeks of ad libitum whole-food intake followed by 2 weeks of unrestricted eating), and 4 weeks of ABD (exclusively animal-derived foods, including beef, pork, chicken, fish, eggs, cheese, butter, and heavy cream, with no plant foods consumed). Energy and protein were tracked at approximately 2000–2100 kcal/day and 170 g/day, respectively. Physical activity, body composition, resting energy expenditure, blood biomarkers, appetite, and eating behaviors were assessed throughout the study. RESULTS: Both diets produced similar reductions in body mass (WFD: 81.3 to 78.2 kg; ABD: 81.4 to 76.8 kg) and fat mass (WFD: 13.6 to 13.2 kg; ABD: 13.2 to 12.4 kg) without meaningful differences in appetite, resting energy expenditure, or eating behaviors. Glucose regulation and renal function also remained relatively stable. However, ABD resulted in less favorable cardiometabolic changes, including increases in total cholesterol (225–466 mg/dL), LDL-C (150–395 mg/dL), and apolipoprotein B (104–253 mg/dL). CONCLUSION: Both dietary phases were associated with reductions in body mass; however, ABD was accompanied by substantial increases in atherogenic lipid biomarkers. Although findings from this single-subject study cannot establish causality or generalizability, they highlight the importance of evaluating cardiometabolic outcomes alongside body composition when investigating restrictive dietary patterns. Further controlled research is warranted.
Recommended Citation
Gafurova, Halema; Franco, Julian; Gonzalez, Adam M.; Tinsley, Grant M.; and Ayesta, Andres
(2026)
"Effect of a Whole-Food and Animal-Based Diet on Health Outcomes: A Case Study,"
International Journal of Exercise Science: Conference Proceedings: Vol. 15:
Iss.
9, Article 9.
Available at:
https://digitalcommons.wku.edu/ijesab/vol15/iss9/9