These people don't have six different diseases. They have one disease, obesity . Cure that and the other problems go away. And just because you hang in a pool, don't think you're immune. Backyard swimmers are particularly susceptible to water loss.
Swimmers lose water through their skin and don' t realize it.
Children dehydrate quickly because of their frenetic movements while playing and chasing. As long as you eat plenty of carbohydrates, the body will burn that and leave the fat alone. The diet of choice ten years ago was a high carbohydrate, low-fat diet. People were exercising six hours a day and eating all these carbohydrates with invisible fat in them. Sort of a one step forward, two steps back situation.