Almost everyone can benefit from eating high potassium foods. However there are some who lose more potassium than usual and have an even greater need. Whenever we lose fluids, we lose potassium with the fluids. If we don't replace it, we will have an even greater deficit than the average American, who gets only about half the recommended daily amount.
Sometimes it will be obvious we need more potassium. When we are sick and have diarrhea, or have been vomiting, or are spitting excessively, we need extra potassium. The best way to get more potassium is to get it in our food. If that is not adequate, we need to take it in pill or liquid medicine form.
Some of the other ways we lose potassium are not so obvious though. Athletes who sweat a lot need extra potassium, as well as sodium. Football players during summer two a day practices can lose up to 3 liters of fluid each practice. Wrestlers who are trying to make weight will often lose weight by sweating and spitting. Athletes vary in how much potassium and sodium they lose in the sweat. It is suspected that this can make some of them susceptible to cramps. In extreme cases, potassium and sodium can become so imbalanced that the heart beat becomes irregular, possibly leading to death.
Patients on diuretics can lose potassium. Many need to take potassium pills to maintain their blood potassium level. They also are susceptible to the irregular heart rhythm and death. Some bodybuilders who have taken diuretics before a contest, trying to look “shredded”, have died.
Hikers may spend a long time without taking in fluid and potassium. Because they are losing fluid through perspiration, even if they do not feel it, they are losing potassium and need to replace it as well as fluid. It seems like every few weeks the news has a story about a rescue or failed rescue on a dehydrated hiker.
Those living in the South or Southwest, especially those doing physical activities outdoors, are susceptible to losing fluid and potassium through perspiration. In the South, the humidity makes you more aware of the sweat. In the Southwest the dry air makes the fluid loss less noticeable, but no less real.
Then finally, there are a few people who should not be eating high potassium foods. Those on potassium sparing diuretics, those with Addison's disease and those with poor kidney function may develop a high potassium level. They should avoid a high potassium diet. Often they require a low potassium diet.