This episode of the Plant-Free MD podcast features Dr. Anthony Chaffee in conversation with Kajan Johnson, a former UFC fighter and trainer. Johnson, who runs a gym producing both recreational martial artists and professional fighters, discusses his extensive career in professional fighting, which began in 2002 and saw him compete globally, including notable bouts in the UFC. He expresses that he is now considering a return to competitive fighting, partially motivated by his positive experiences on a carnivore diet, which he wants to test live in various fighting disciplines.
Johnson’s journey to the carnivore diet was influenced by his mother’s health transformation. After 30 years as a vegetarian, her health declined significantly, leading her through low-carb and ketogenic diets before settling on a carnivore approach that drastically improved her health and appearance in her 60s. Witnessing her recovery and hearing about other endurance athletes thriving on similar diets piqued Johnson’s interest, as he was constantly seeking an edge for himself and his team in the demanding world of combat sports. Despite previously struggling with sugar addiction and experiencing related problems like getting sick more often, he eventually transitioned to a carnivore diet.
Since adopting the carnivore diet, Johnson has observed significant improvements in his physical and mental state. He notes better gut health, feeling more solid in the abdomen, and less issues with phlegm, which previously hampered his breathing during sparring. He also finds that he recovers quickly from training and injury; a torn MCL, the catalyst for him finally committing to the diet, healed rapidly without traditional rehab efforts. Mentally, he experiences greater clarity, focus, and quicker decision-making, reporting that his mind is less prone to racing thoughts, which he correlates with potential ADHD symptoms. Regarding energy levels, he finds them fantastic and feels able to push through tiredness like a “steamroller,” noting no loss of explosive power and potentially feeling faster mentally. He also experiences less soreness from training activities like jiu-jitsu and sparring compared to his previous diet.
A significant point of discussion is the common belief that athletes in explosive sports require carbohydrates. Johnson mentions his team expressing this concern, citing textbook information suggesting fat burning is not maximally available until after 20-40 minutes of exercise and that explosive power is reduced on low-carb diets. Dr. Chaffee counters this by explaining that ketones, derived from fat, are readily available fuel sources that the brain and muscles prefer, even over glucose when present in abundance. He refutes the idea that dietary carbohydrates are essential, citing historical examples of carnivorous populations. Referencing studies like the FASTER trial and M’Sweeney trial, Dr. Chaffee highlights research indicating that keto-adapted athletes can oxidise fat at much higher percentages of V2 max than carb-fuelled athletes and that ketogenic groups in studies have outperformed carb groups in both endurance and, significantly, explosive tests like sprints and critical power tests, particularly after an adaptation period.
Beyond performance, the conversation touches on other benefits. Dr. Chaffee discusses how ketogenic diets can be beneficial for traumatic brain injuries (TBI) and concussion recovery due to ketones’ anti-inflammatory properties, which can help reduce post-concussion swelling. Regarding weight cutting, a crucial aspect of combat sports, Johnson notes that being carnivore leads to less water retention, making his weight more consistent. While he ponders how traditional water manipulation strategies used by carb-eating fighters will apply, Dr. Chaffee suggests that the decreased water retention from eliminating plants and carbs means there is less “bullshit water weight” to cut in the first place, leaving athletes leaner with more proportional lean body mass. This is seen as a potential advantage, although cutting less water weight might mean being lighter in the cage compared to opponents who cut significantly from higher starting weights due to carb-induced water retention. Johnson remains excited about the potential advantages the diet offers for competitive fighting, including increased competition frequency due to faster recovery.