I think in general, people from tropical countries tend to be naturally fit whether it be from walking around a lot, doing manual labor, or being active at the beach and other active activities like dancing. It’s more built in their lifestyle. Being outside a lot in hot weather makes you more thirsty than hungry.
I have a friend from Rio. He says he goes swimming a lot and often goes out dancing on weekends. Plus in hotter countries, they usually have a larger access to fruits and vegetables compared to people of moderate climates. Even the Blue Zones, which are known to have the healthiest old people, are located in or near the tropic zone.
I hope to visit Brazil one day because I trained their art, capoeira, for 5 years. It’s only right to do it in its birthplace. Swimming will be interesting since I usually wear more modest swimwear. I guess laser and chemical hair removal must be the go to thing there. Funny enough I get Brazilian bikini waxing, but you need to wait until the hair grows back to a certain length. That won’t work for someone who regularly goes to the beach.