I actually very much see veiled's point, and concur, in that it is the idea behind being skinny that is the issue, not a person being skinny as such, male or female. Some people are naturally very slim, regardless how much they eat. If any person lives on junk, they will eventually put on weight with age. Now, under weight and over weight both have there health issues. So what is the right thing? To simply eat healthy, exercise, and your body will take over naturally for your correct weight balance. To starve yourself to achieve size zero is one thing, but to eat healthy regular meals and be a size zero is another. One not healthy, the later quite healthy.
I know women who are extremely petite, to say the least, some eat like horses, exercise lots, and simply can't put on weight, as that is their bodies natural build and size when eating healthy, others eat little to maintain a figure for societies value and perception, all the while their body is craving minerals and nutrition, thus they tend to become sick and unhealthy eventually as a result.
Big difference in how you word what is, and is not healthy, for any size IMO. Talk with a dietition, and you would likely get the same type of response.
Its like 99% of over-weight people who try and tell you that its hereditary, when in fact you watch what they eat, and its exactly that, what they are eating and the quantity of food they consume. I used to hear it all the time in the military, with people being over-weight, and when you looked at their diet, you could see the issues immediately. Amazingly enough, when they changed their eating habits and stuck with them, suddenly the weight fell off them, they became fitter and found life much easier being healthy, their ideal weight. Very few people are naturally obese from genetics, the same as very few are naturally a size zero from genetics.