Wrong visualization method. They should have used a Ternary plot. https://en.wikipedia.org/wiki/Ternary_plot
There's no way to fit salad (0,1,0), soup (1,0,0), and steak (0, 0.5, 0) on the same ternary plot because the first two points add up to 1 and the last one add up to 0.5.