Slow metabolism is an organisms' response to starvation. Cave men had extremely slow metabolism as they only ate once per few days or so. Having slow metabolism can be good (you burn your calories more efficiently) but that also means that your body will store all calories you eat and transform them into fat. In modern world there is no need for having slow metabolism as food is no problem (well, at least in most part of the world). If you have the chance to eat more often per day than by all means do so. Having faster metabolic rate is very beneficial as it improves weight loss and helps you maintain target weight. You can calculate your own basal metabolic rate using this BMR calculator. Have in mind though tha tBMR is just a mere approximation of your daily caloric needs. BMR calculator usually works on a linear formula and as such cannot be accurate.