When I was in university, one of my courses introduced me to two words: Marasmus and Kwashiorkor. The first condition - Marasmus - is the image of a starving child which one normally sees on tv. It is the child starved to the point of having prominent ribs and his or her muscles have wasted away. The second condition - Kwashiorkor - is also a form of starvation but wouldn't garner much sympathy because the child appears to be not only well fed but overly fed. The child does not have prominent ribs and the belly appears to be fat. It isn't fat though. It is distended due edema. These images have left an impression in the back of my mind that sometimes people who appear to be fat are not fat because of too much food but perhaps due to the lack of proper food.
Over the past few years a number of people who are related to me have experienced tachycardia. Obviously it could be a genetic anomaly or possibly there is something else in play. Perhaps it is an artifact of diet. Families tend to have a set recipe book of foods that they eat. If it is lacking in certain nutrients than it could lead to problems. Historically we were a meat and potatoes family. Both beef and potatoes are high in potassium and a reasonably quantity of magnesium (if using baked potatoes and skins). As time passed most people have moved into a diet with foods with lower quantities of both of these nutrients. How many people actually eat 7-10 cups of leafy green vegetables per day.
I have a hypothesis that a potassium poor diet is one of the factors which drives people to being overweight and diabetic. Think of potassium is a door lock into a cell and insulin acts a key. With insufficient doors working (lack of potassium) more keys (more insulin molecules) are needed to open existing doors. A [study] (https://www.ncbi.nlm.nih.gov/pubmed/8794828) showed that when an inhibitor (ouabain) of the sodium potassium pump was introduced vasodilation was inhibited (the control state) but this effect was reversed with the addition of insulin. My hypothesis is that instead of an inhibition - what if it is a deficiency of potassium is what induces the first stages of insulin resistance and once it is started it goes into a feedback loop even if potassium levels are brought back to requirement.