IIFYM Expert Review Board and Editorial Team
At IIFYM, every calculator, recommendation, and nutritional guideline is reviewed by qualified medical professionals and registered dietitians. Our expert review board ensures all content aligns with current evidence-based nutrition science and meets the highest standards for accuracy and safety.
Our team includes medical doctors, registered dietitians, and certified specialists with decades of combined experience in metabolism, endocrinology, sports nutrition, and evidence-based dietary strategies. Below you’ll find detailed credentials for each member of our review board.
Dr. Ioannis Nikitidis, MD, RD
Medical Doctor & Registered Dietitian | Endocrinology Resident | Certified Obesity Specialist
Dr. Ioannis Nikitidis is a Medical Doctor and Registered Dietitian who medically reviewed and approved the IIFYM macro calculator for accuracy, safety, and evidence-based methodology. He specializes in endocrinology, metabolic health, and obesity medicine, bringing critical medical oversight to all nutritional recommendations.
Dr. Nikitidis completed his medical degree and dietetics training in Greece, where he practices as an Endocrinology Resident. His clinical focus includes metabolic disorders, thyroid dysfunction, diabetes management, and weight regulation. He is a Certified Obesity Specialist with expertise in the hormonal and metabolic factors that influence body composition.
As a member of the IIFYM Expert Review Board, Dr. Nikitidis evaluates all calculator formulas, macronutrient recommendations, and safety disclaimers to ensure alignment with current medical literature and clinical best practices.
Justina Serwaah Owusu, RDN
Registered Dietitian Nutritionist | Research Scientist | Florida International University
Justina Serwaah Owusu is an evidence-based dietitian and research scientist who reviewed and approved the IIFYM macro calculator for nutritional accuracy, metabolic safety, and alignment with Academy of Nutrition and Dietetics standards. Her research background ensures all recommendations reflect current nutrition science.
Justina earned her degree in Dietetics and Nutrition from Florida International University, where she continues to work as a Research Scientist. Her academic focus includes evidence-based dietary interventions, metabolic health, and the translation of nutrition research into practical recommendations.
As a member of the IIFYM Expert Review Board, Justina evaluates all macronutrient calculations and dietary guidance to ensure alignment with peer-reviewed research and Academy of Nutrition and Dietetics standards.
Anthony Collova
Founder & Creator of IIFYM | NPC Bodybuilder | 15+ Years Coaching Experience
Anthony Collova created the world's first macro calculator in 2012, pioneering the IIFYM flexible dieting movement that changed how millions approach weight loss. What began as a simple tool built for his own bodybuilding prep became the foundation of a global shift away from restrictive dieting toward sustainable, science-based nutrition.
With over 30 years of experience in fitness and bodybuilding, Anthony has competed as an NPC bodybuilder and trained alongside some of the top names in the sport. His hands-on experience with contest prep, reverse dieting, and metabolic adaptation informs every aspect of the IIFYM methodology.
As a nutrition coach, Anthony has personally worked with over 500 clients and built systems that have helped more than 50,000 people calculate and track their macros. His coaching focuses on sustainable fat loss for people over 40 who have tried restrictive diets and failed.
Anthony developed the proprietary formulas behind the IIFYM macro calculator, incorporating adjustments for metabolic adaptation, activity level, and individual body composition that generic calculators miss. These formulas have been validated through over 10 million calculations since 2012.
While not a credentialed medical professional, Anthony works directly with the IIFYM Expert Review Board to ensure all calculator outputs and nutritional recommendations meet current evidence-based standards. Every formula and recommendation is reviewed and approved by Dr. Ioannis Nikitidis, MD, RD and Justina Serwaah Owusu, RDN before publication.
