I wonder why there are standards that focus to generalize everyone to follow specific categories. Is it unhealthy to have excess body fat? Generally yes. Always? Hell ****ing no. Consider me, 24 years old, weighs 350lbs, measures 6'4, 46" waste, 35% body fat. The vast majority would consider this disgusting. However, there is more to it than simple BMI scale, which IMO is total horse****.
I eat 1800-2400 calories per day, and I prefer healthy over greasy. I can lift 220lbs with my arms or 500lbs with my legs, which is in addition to my own weight, not inclusive. My active duty blood pressure is 125/90 and resting pressure at 115/75. I can move large pieces of furniture by myself when a pair of two have trouble. Walking distance is limited only by my flat feet (ow!). I can cycle for miles without getting too tired. I've been solicited more than once by my college's football coach to try for center position. I'm regularly asked if I'm the bouncer whenever I'm at a bar. This doesnt fit the 'standard' profile of someone my size, now does it... So the question is, why do I weigh 350lbs? Three reasons, all of which are physical.
First of which is that I'm a survivor of a may-as-well-be near miscarriage, and I had many difficulties in my earlier development. One such difficulty is overall dyspraxia. It wouldn't be wrong to say it is similar to a mild form of Cerebral Palsy. My gross motor development is significantly hindered by this complication, and as a result I am slow and clumbsy, which itself leads to low metabolism. Thank god my fine motor development was well above average.
Secondly, I have a rare blood hemoglobin type, known as LAC Hemoglobin. This is due to someodd mutation during fetal growth. It is similar to Hemo C, but with a few differences I dont know or care about. But it causes an atypical shortage of blood cells... In a simple word, anemia... I also have thallasemic anemia, which further complicates things. My blood cell count is approx 60% of an average person my size. This too contributes to a slowed metabolism.
The final reason I am how I am is just because I choose to be built this way. I was born 2 weeks premature, and I was announced at 11lbs 14 oz. The doctor said I was gonna be huge. However, as I was growing up, I was smaller than anyone you'd ever see for my age. In primary school, I was unable to perform physical activity. Even the smallest amount of activity would knock the wind out of me. In 8th grade, an assistant bus driver asked me if I was lost. I was small, weak, and barely able to hold my own weight... That is until I finally got my growth spurt and grew both up and out. In 3 years, I gained about a foot in height, and 200lbs in weight. After that, I was large, as well as strong. And it's always been my idea that I'd rather be large and strong than small and weak.
In short, I'm healthier as a big guy than I am as a small guy. So forgive me if I take the 'if you are this tall, your optimal weight is this' rule as a very generic grain of salt.