It's an interesting graph but doesn't adjust for protein bioavailability 

 I came to say the same thing  

 What about zee bugs? 

 Mushrooms can be cheap depending on where you live. 

 Makes me think that if you wanted to eliminate an affordable source of protein, afflicting folks with peanut allergies isn't a bad idea. 

 It'd be interesting to do a longevity study based on main source of protein over a lifetime 

 Legumes making a strong showing if you're on a budget 

 Neat chart but “protein density” is a somewhat misleading metric. The protein in a ribeye has magnitudes more amino acid content than an equal amount of pea protein gram for gram, for instance. 

 Proteins are just chained amino acids, so what you're saying doesn't make any sense at all.

There are of course also differences in fatty acids, minerals and vitamins content 

 Not all proteins are created equal.

According to DIAAS (“Digestible Indispensable Amino Acid Score”):

Beef 1.12
Peas 0.65 

 Meat has all the amino acids. Peas do not. 

You could survive eating only meat. 

If you were to eat only peas, you would absolutely die. 

 Neato. Now plot Omega3:6 ratio. Beef starts looking a lot better on that chart, I bet. 

 Legumes being that high blows my mind.  Always thought of them, with peanuts being an exception, as being over starchy. 

 It seems like bone mass alone is not enough to explain the difference in protein density between a chicken drumstick, chicken wing, and chicken breast. 

 Very interesting! been vegan for almost 8 years and had working really well for me. The only thing to be really careful of is which fat you use. And processed food obviously.  

 Do you supplement? 

 neat visual. needs chicken thigh - phenomenal bang for the buck plus flavor.