After South Africa started limiting salt in processed foods, people in a rural area were found to be eating less salt — and that drop stayed steady for years.

After South Africa introduced rules to reduce salt in food, more older adults in rural areas started eating less salt — the number doubled from 7% to 17%.

In older adults in rural South Africa, the less salt they eat, the lower their blood pressure tends to be — every gram of salt saved drops blood pressure by a small but measurable amount.

City-dwelling adults in Cameroon are excreting way more salt in their urine than people living in the forest who hunt and gather food — more than double — which probably means they're eating a lot more salt in their diets.

If you eat a lot of salt—like 18 grams a day for 10 days—your body will flush out more salt in your urine and also have a bit more salt in your blood, which proves you actually ate the salty food they gave you.

If you eat a lot of salt—like 18 grams a day for 10 days—your body will pee out more salt and your blood will have a bit more salt too, which proves your body is responding as expected to the extra salt.