Neanderthal diet: 80% meat, 20% vegetablesIf you read this article you discover that this study is based on one population of Neanderthals from one site in Germany around 40,000 years ago. It's like studying the bones of medieval European peasants and saying, Human diet: 80% bread.
Neanderthals were a cold-adapted breed, so perhaps they generally had meat-heavy diets like Arctic people today. But they, like all other hominids, could eat a variety of foods, and I am quite certain that their diets varied enormously across their large range.
There was no single "paleo" diet. The diets of ancient humans probably varied as much as those of modern hunter-gatherers, that is, the percentage of calories from meat and fish ranged from more than 90 percent to as little as 20 percent. Maybe Neanderthals had a narrower range than that, but I doubt it was very much narrower.
It can never be said too often that the most important thing about humans is our diversity.