With respect I am qualified to degree level in nutrition and physical activity, so am confident of what foods are classed as protein rich and what are not. If you read your own link you will see there is <1g protein in a cup of spinach and ~2.5g in a cup of sweet potato, they are hardly a good source of protein you would have to eat kilograms each day to make it worthwhile AND they are not complete so you'd need to combine with another vegetarian source (beans, lentils, nuts, seeds).
It's actually far more useful to look at protein as a percentage by weight, cups are a highly misleading and unscientific way of comparing foods. Protein rich foods include meat, fish and seafood, many cheeses, eggs, nuts, seeds, Quorn; to a lesser extent beans, lentils, soya, milk and yoghurt.
2a-2c, medium texture, porous/ colour treated. Three years CG, growing out mechanical and chemical damage = breakage and very high porosity. Past armpit length heading for waist.
Treatments: Komaza protein, Komaza Matani, coconut oil with sugar syrup. Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume
Styler: Umberto Giannini jelly, Boots curl creme, Rockin RInglets
Experimenting with: Mega-Tek, Curl Harmony reviver, Elvive Full Restore 5.