This is both fun and serious question at the same time.
Obviously, humans and lions are two different genera and species. But they both are mammals and the similarity ends between the two ends here.
The serious part of the question is that is eating too much meat cause diseases in human. Plant-based food consuming enthusiasts will claim that meat should be completely abjured. There are vast sections of human societies especially living in North Asia (Japan, China, Northern parts of Russia in particular) where the diet is rich in fish and other seafood. Many of the longest living humans come from these regions.
Meat if it is low in saturated fats and is free of antibiotics is a great source of protein. Meat is rich in Vitamin B12, Omega3 fatty acids, heme iron all of which are critical nutritional components. A vegan diet requires to be supplemented to make it nutritionally holistic.
Ours is a diverse planet that has variations of cultures, tastes, and eating habits. But there are universal fundamentals of healthy eating. Let me summarize some of them here:
Food should be rich in fiber and antioxidants but is low in saturated fats with a preponderance of mono-unsaturated fatty acids. Carbohydrates are essential for our bodies and provide us energy. Resistant starches are a good option. These can be found for instance in banana. Protein is critical to the development of the human body. Most muscle and this includes the heart muscle is proteinaceous.
If you select the right meat you are fine. But don’t go ahead a fix a large fat dripping steak because it gives you essential protein. That will take you on the high road of cardiovascular ailments, diabetes, and obesity.
To get to know more about Nutrition Facts, check here.