I don't know where the larger locals shop at... I want to ask one: "Hi, you are about as fat me - where do you buy clothes?" But I may need to reword that....
My shoe size is only a US 11 and I had a <Snip> of a time finding shoes. I wear 1X pants & shirts in US sizes. I have shorts that I bought here. Some 3X and some 5X. The 5X are smaller than the 3X? Good luck.... Some of the high end shops at SM will have US sizes, but higher than US prices, from what I have seen.
I was at a no name shop today at Merrymart, Iloilo. They had Under Armor shirts in US 2X that actually fit me. But... for p250 I know they are knock offs. I don't know how long they will last. The name of the shop has always confused me "Unsanity". Is that a misspelling of insane or unsanitary?