Healthy nutrition and exercise for the minority somatotype?

[KonstantinM]

I got an impression that most of the advice out there on healthy diet is implicitly tailored for overweight people or at least those who have a tendency to gain fat. On the other hand what's usually suggested for the lean/skinny/high metabolism ones is usually.. well, in fact plain overeating and weight training (for men), obviously with the aim of making their exterior more curvy/muscular. Although I do care to some extent about my sexual appeal, I'm more concerned with feeling generally well, being energetic and healthy. I'm not sure it's wise to do things with my body exactly converse to what it's naturally suited for. Are there any ideas or resources on this issue?