What's That Rash? — "Why the Carnivore Diet is So Risky"

ABC News | April 22, 2025

Overview

This episode delves into the popular but controversial carnivore diet, exploring its purported health benefits, real scientific risks, and sociocultural context. Recording from a live show at the World Science Festival in Brisbane, hosts Tegan (A) and Norman (B) answer audience questions, break down nutritional science, and inject humor while scrutinizing extreme dieting trends.

Key Discussion Points & Insights

1. What Is the Carnivore Diet? (03:07–05:41)

• The carnivore diet consists exclusively of animal products—typically red meat, eggs, and high-fat options—while eschewing all plant-derived foods.
• Typical daily intake:
  Breakfast: Bacon and eggs (no toast)
  Lunch: Fry pan of ground beef (no fiber, minimal Maillard reaction)
  Dinner: Steak with salt—often choosing high-fat and costly cuts like Wagyu
  Snacks: Sometimes just a stick of butter, or "bulletproof coffee" (coffee with butter)
• Carnivore diets are "almost no carbohydrates, very high fat—like 60, 70% fat and the rest protein.” (B, 03:46)

2. The Fiber Problem & Constipation (05:13–06:11)

• A major side effect: constipation due to "just zero fiber.” (A, 05:52)
• Some believe increasing fat intake "just slides out of you," but this is "because the fat doesn't get absorbed." (B, 06:06)
• Humorous note: Carnivore dieters’ toilets are "sparkling clean…because you're constipated and you never use it." (B, 05:47)

3. Did Cavemen Really Eat Like This? Debunking Paleo Myths (06:15–09:32)

• Claims that the diet mimics "what cavemen ate" are oversimplified.
• Ancient diets varied widely by geography and season; most Paleolithic humans ate a great variety of plant-based complex carbohydrates and whatever was available for foraging.
  • "Every Paleolithic diet pretty much had complex carbohydrate in it, just of different kinds." (B, 07:29)
• Archeological evidence (e.g., caves in Morocco): early humans consumed acorns, pine nuts, pistachios, oats, and legumes—ground teeth and starch decay confirm this.
• "Humans are incredibly adaptable and able to live under a lot of different conditions in a lot of different diets." (A, 09:15)
• "We are omnivorous indeed, just part of our survival.” (A, 09:33)

4. Are Plant Foods "Toxic"? (09:33–10:11)

• Some plants contain mild toxins (e.g., alkaloids in unsoaked legumes), but “meats can be contaminated as well."
• Both food groups have risks, but modern preparation and cooking practices mitigate them.

5. Scurvy: Can You Survive Without Fruits and Veggies? (10:11–11:56)

• Scurvy (vitamin C deficiency) is a legitimate risk on strict animal-only diets.
• Some traditional populations (e.g., Inuits) avoid scurvy via small amounts of vitamin C found in raw animal products and metabolic adaptations.
• "Evidence suggests people on a carnivorous diet are low in vitamin C…teetering." (B, 10:35)
• Notable Case: “Scurvy in an Unrepentant Carnivore”—the patient got scurvy twice after adhering strictly to a carnivore diet and recovered only with vitamin C. (A, 11:31)

6. Why Do Some People Feel Good on It? (12:35–13:34)

• Carnivore diet functions as a strict ketogenic diet (very low carb, high fat/protein), producing "ketone bodies" for energy.
• Many initially feel energized and report appetite suppression and weight loss, but side-effects include "constipation" and "keto breath."
• Life expectancy in the Stone Age: “28, so just be careful what you wish for." (B, 13:30)
• This sense of well-being is common to restrictive, rapid fat-burning diets, not unique to carnivore eating.

7. What Does the Science Say About Long-Term Risks? (13:39–18:20)

• Reliable long-term studies are lacking; most data is self-reported and lacks objective health outcome measures.
• Carnivore diets are often associated with extremely high cholesterol and LDL ("bad cholesterol") levels:
  • “Their total cholesterol levels exceeded 25, significantly higher than his baseline level of 5 to 7 millimoles per liter.” (A, 15:20)
  • Extreme cases can lead to xanthoma/xanthelasma—visible fat deposits under the skin and in the eyes.
• "The higher your LDL, the higher your risk of coronary heart disease, stroke, and dementia.” (B, 16:59)
• Red meat consumption, especially bacon and processed meats, is strongly correlated with increased risk of "colon cancer, large bowel cancer."
• Some short-term benefits do exist: improved vitamin B and thiamine levels; however, LDL levels tend to be “around about 4.5, which is very high, so at least twice what you'd consider a normal level." (B, 17:56)
• “Red meat is strongly associated with colon cancer.” (B, 18:16)

8. The Diet and Pop Culture/Politics (18:20–19:09)

• Hosts discuss the carnivore diet’s popularity among certain political and social figures:
  • "There's a real correlation between people who are interested in these sorts of diets and a certain bent of politics." (A, 18:28)
  • It ties into contrarian, macho, or anti-establishment narratives: "the Andrew Tate, Joe Rogan kind of story—that real men eat meat and they don't eat vegetables." (B, 18:56)

9. Takeaway: Is It Ever a Good Idea? (19:09–20:04)

• Short-term: Possible weight loss and increased energy due to caloric restriction and ketosis. May benefit blood sugar control for some diabetics.
• Long-term: High risk of cardiovascular disease, dementia, nutritional deficiencies, and likely unsustainable for most.
  • "In the long term...it's going to clog up your arteries, increase your risk of dementia and it's not a healthy way to do a ketogenic diet." (B, 19:34)
• Healthier alternatives exist: balanced ketogenic diets with some plant foods for fiber and micronutrients are possible.

Notable Quotes & Memorable Moments

• "Constipation is one of the problems of the carnivore diet because there's just zero fiber in it…That's why this toilet is so sparkling clean."
  — Norman (B), 05:47

• "Every Paleolithic diet pretty much had complex carbohydrate in it, just of different kinds, depending on availability."
  — Norman (B), 07:29

• "Humans are actually incredibly adaptable and able to live under a lot of different conditions in a lot of different diets. We are omnivorous indeed, just part of our survival."
  — Tegan (A), 09:15–09:33

• "Evidence suggests people on a carnivorous diet are low in vitamin C…teetering."
  — Norman (B), 10:35

• “Their total cholesterol levels exceeded 25, significantly higher than his baseline level of 5 to 7 millimoles per liter. It came out in an unusual way, literally.”
  — Tegan (A), 15:20

• "The higher your LDL, the higher your risk of coronary heart disease, stroke, and dementia...Red meat is strongly associated with colon cancer."
  — Norman (B), 16:59, 18:16

• "There's a real correlation between people who are interested in these sorts of diets and a certain bent of politics...the Andrew Tate, Joe Rogan kind of story that real men eat meat and they don't eat vegetables.”
  — Norman (B), 18:28–18:56

Audience Q&A: Microbiome and Ileostomy (20:20–21:58)

• Question: How does the lack of a large intestine (post-ileostomy surgery) affect health, given the microbiome-brain axis?
• Response: No comprehensive studies yet, but missing the large bowel changes the microbiome substantially. Other body sites still host microorganisms, so all is not lost.
• Prebiotics, rather than commercial probiotics, are recommended for microbiome support. The best prebiotic diet? (Hint: it's not the carnivore diet.)

Epilogue & Tone

The hosts round out the episode by ringing their “Mediterranean diet” bell—suggesting a return to proven, balanced, plant-inclusive diets—and thanking the live audience for engaging questions.

Summary Takeaway:
The carnivore diet may provide short-term weight loss and a sense of well-being for some, but carries serious long-term health risks—especially for heart, colon, and cognitive health—according to the current science. Human beings evolved as versatile omnivores, and the best path forward is a balanced, fiber-inclusive diet.