There is no slow or fast metabolism, that is misinformation we often hear. Your metabolism is based on how active you are and the more you weigh, the more calories your body needs to maintain that size. So if a 500 lb person decided to eat 2,000 calories a day, they would actually lose weight despite that they sit around. People who weigh that much have a food addiction and they have underlining issues because no one eats themselves to 500 lbs unless they have other issues going on.
Most people are overweight because of what is in our food that makes us want to eat more, it's our life styles we have like how many of us have desk jobs? Also it's what we eat. Sure if you have a job where you work on your feet all day, you will have "fast metabolism" because you are using more energy so you will need more calories than someone else who has a sit down job and doesn't get much activity. There is a saying "move more, eat more."
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Son: Diagnosed w/anxiety and ADHD. Also academic delayed.
Daughter: NT, no diagnoses.