Wow, so this is a huge question. Let me address some issues, and then I will dive into the question.

First, the human diet is remarkably diverse based on seasonality and geographic location. In the far north our species can survive on diets consisting of mostly meat, while others in more temperate regions can flourish with practically no protein intake from meat resources. Our diets change based on the time of year and the resources available. We stock up on nuts and tubers when they are in season, or dry meat after a large kill is made, to preserve resources for leaner times. Members of our species, for a huge variety of personal or cultural reasons, voluntarily avoid potential food resources despite their abundance. There are two constants to our diet: a reliance on nutrient-rich, difficult to extract resources, and extreme variability in the resources we utilize.

Second, due to the preservation problem, we may never know the complete components of human diets in the past. Hardier substances like animal bone and marine shell readily preserve, while remains of delicate leaves, fruits, and other softer materials might not survive to be recovered by paleoanthropologists. We may overestimate the relative importance and dependence on hunted/scavenged meat resources in the past simply because those materials have better preservation.

That said, an examination of modern foraging populations can provide some insight into the components of foraging diets. We should not assume they represent our hominin ancestors, they simply provide a window into the diversity to be found in foraging groups.

Kaplan and colleagues examined the daily energy production of men and women in ~10 different modern foraging groups. They found the mean total calories foraged in the different groups ranged from ~1,000 to over 8,000 calories per day. Males tend to focus on meat resources, and forage anywhere from 2,000 (Anbarra) to 8,000 (Hadza) calories a day, on average. Females tend to focus on roots, fruits, and other resources, and their daily caloric return ranges from 916 (Hiwi) to 4,397 (Hadza) calories per day.