It'd have probably been easier to manage when we didn't have to put hours of intense exercise in bursts to compensate for working in offices and stores, and instead did physical labor.
Eating lots of legumes and groats to fulfill protein needs is more viable if the calories are needed for your daily labor, then the starches are an upside.
Tofu fortunately makes things easier, but it's not always readily available in many places where its consumption wasn't a cultural practice already.
Still, you've got to pay attention to eating some protein in every meal, and if you're in the West and similar (Latin America will have many of the same patterns, but I'll always find it weird it's not considered "Western" culturally despite being an offshoot of Spain), you may have to deviate plenty from the diet of your culture.