I have a very high metabolism. Some envy me, others find me too skinny. What troubles me though, is that I don't have weight as a heuristic in regards to my hea

I have a very high metabolism. Some envy me, others find me too skinny. What troubles me though, is that I don't have weight as a heuristic in regards to my health. I sometimes worry, as everything else is quite ambiguous. Energy levels depend on sunlight, sleep and so on. How often I fall sick is equally dependant too many variables for it to be a reliable indicator. I would love for something like this to be reliable/easy/cheap so I have something I can turn to when I feel uneasy about my health.