First of all, eat greens and beans.
On top of that, eat fruits and roots.
And last not least, eat nuts and seeds.
Divide your daily caloric intake about 60/35/5% in the first, second, and third group. Remember that the greens have very little calories per volume, so you'll need to eat a lot. Conversely, nuts and seeds are very dense in calories (especially fats), so you'll only need to sprinkle a few on your salad or blend them into a dressing.
Remember, unrefined plant foods (including mushrooms in the first group) are the only foods allowed, so there's no sugar, oil, or flour, or anything made of sugar, oil, or flour anywhere near allowed!