When your job is to survive in that age, you have to seek food almost 24x7. At that, you’re bound to run into fruits, veg and nuts. And early hominids didn’t have to carve out time in their day to exercise. Survival was tough. Chasing down game is plenty good enough.
I have watched all the seasons of the show “ALONE”.
Where they drop ten people off at some remote location and the last one there wins.
The first couple seasons the people who were good at foraging won. Finally there was a guy who killed a muskox with an arrow. Then stabbed it with a knife to kill it. He won because he had enough meat to survive long term. Even the people who were really good at catching snow shoe hares could not maintain their body weight because they did not have enough fat in their diet. Hares are very low fat meat.
Ever since that season the winner was typically the person who was able to kill a moose, a deer or a whole bunch salmon/lake trout/fish. Eating berries and mushrooms supplements the diet but it does not replace the PROTEIN and FAT in animal/fish meat/fat.
Actually studies over the past century indicate that hunter/gatherer societies only spend about 27 hours a week seeking food. Since they are not capitalists, they are not trying to have big surpluses, so the 40 your week is not their norm.