thats a myth!
eating right and exercising is the only way to be lean..that can also be achieved by non-veg..in fact many people on diet have grilled chicken..depends on what you eat, how much you eat & what time you eat
You can also have veg biriyani..veg pizzas and we all know where your weight will go with that..
so no i don't think they do it to stay thin..
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