It's better to play in ½ speed, villagers eat less. For example, I began a new tribe yesterday (in normal difficulty because I'm bored to run after food as in my previous tribes):
With 7 people, when the algae came I was able to buy the level 2 of Engineering and I put 5 villagers on building the dam and 2 children (and 726 points of food from fishing, I didn't have coconuts). I spend my time with children picking mushrooms and collectibles. 2 hours later, the dam was build and I wait 1 hour and ½ for new crops. When crops arrived, I had around 880 points in the bin without coconuts.
But it was in normal difficulty, ½ speed and looking for mushrooms all the time! In hard difficulty, you need the coconuts and try to don't miss a mushroom!! It is possible with 10 but no many more. (and in 1/2 speed)