If meat eating is what you say it is then carnivores like tigers and lions would have been sending spacecrafts to Mars not humans because an average carnivore eats a lot more meat than an average human.
Lions and tigers are different organisms with different evolutionary paths. Meat eating made us smarter.
Food For Thought: Meat-Based Diet Made Us Smarter
Our earliest ancestors ate their food raw — fruit, leaves, maybe some nuts. When they ventured down onto land, they added things like underground tubers, roots and berries. It wasn't a very high-calorie diet, so to get the energy you needed, you had to eat a lot and have a big gut to digest it all. But having a big gut has its drawbacks. "You can't have a large brain and big guts at the same time," explains Leslie Aiello, an anthropologist and director of the Wenner-Gren Foundation in New York City, which funds research on evolution. Digestion, she says, was the energy-hog of our primate ancestor's body. The brain was the poor stepsister who got the leftovers. Until, that is, we discovered meat. "What we think is that this dietary change around 2.3 million years ago was one of the major significant factors in the evolution of our own species," Aiello says.