I was 100% animal based nutrition for 8 weeks in 2019. Meat (primarily red meat), butter, and eggs. Initial adaptation took about 4 weeks. Once that was done, I experienced the most profound changes in overall sense of wellness. Calm, stable mood but at the same time healthy level of desire to live life aggressively. Markers of male hormonal health were high.
At 5'8", 158 lbs, I felt like I could rip through a wall. I looked forward to every meal and never felt sluggish or tired from eating. I was at my highest level of power and strength relative to the lowest adult weight in my life. All joint pain vanished. The fat seemed to melt off with no real effort toward that end. I suspect that the high protein and increased satiety of meat had me eating at a caloric deficit, at least for the period of time. Overall, I've never felt so good.
I stopped because I knew that at some point I would not be able to eat this way for the rest of my life, so I didn't see the point in continuing. I missed having fruit as well as a variety of foods.
If you are interested, Dr. Paul Saladino has done a lot of work in this area. He suggests a carnivore-adjacent way of eating (80-90% animal based) still results in significant improvements to health that still allows room for better tolerated plant foods like, certain lettuces, avocados, olives, seeded and skinned cucumbers and squash and low sugar berries. He does advocate for a 100% carnivore nose-to-tail approach, however recognizes this approach may not be practical for all. He has a great podcast called Fundamental Health. I highly recommend it.
EDIT: Vince Gironda was the father of the "Steak and Eggs Diet back in the early 60s". Meat and eggs for 4-5 days and then eat veggies and carbs for a day, then back to steak and eggs. Rinse and repeat.
