When it comes to protein peanuts have more protein then chicken and many other alternate options are present
If you want to say that protein intake makes body bigger and bulky it's your misconceptions
It's totally based on genetics and lineage
South Indian are mostly non-vegetarian and includes fish in daily routine still shorter and lean than Indians from north where half of the population never touch flesh and other than tastes once a while
Same concept with japanese chinese Indonesians etc there is plenty of non veg in their food still shorter and lean
So on my opinion body of a person depends on his lineage history and geography