Does being thin pose any health risk?

First of all,can u find out the body mass index ? If it is below 18, then u need to consult some good doctor.But if it is between 18 to 22 then its quite alright.Some people as such have got a thin body structure..if she is active and other ways quite normal,then dont think u need to worry.

no , being thin is sometimes from genetics like if your sis is thin then her mom or father may be thin or like she takes more time to eat food, recently it is proved that the persons who take more time to eat food are more thinner than the person who eats faster. the main things are food she takes if that are healthier than there will be no problem

ya it can be genetic..and being thin cannot be health risk even iam thin...i don't fat how much ever i eat.

i think the way in which the ideal thin body type is marketed by the media makes being thin a health risk

It cannot be implied by just being thin or bulge imposes a health risk or not. But it depends on the internal defence power and nutrition of the person. A person may be thin but has enough internal self defence for disease and take adequate amount of nutrients (as fat is not the only nutrient), then there is minimal health risk for him. On the other hand a bulge person like only to eat fatty and oily substances and does not take adequate amount of other essensial nutrients, then he has quite a risk of being attacked by diseases

One of my daughters is 16 and she is very tall and very thin. I was worried about her weight so I took her to my doctor for a check-up. She is way above the height range for her age (she is about 5'10" right now and will probably be taller than 6' when she stops growing!) but her weight is in the mid-range, heading towards low. The doctor told her that she is ok at the present time but that she must continue to eat well. I thought it was important for her to hear those words from a doctor and not from her mother. She doesn't have any health problems at this time, except that her blood pressure is a bit low. The doctor gave her some solutions to use to keep things balanced. Now, one of my longtime friends, she has been extremely thin for her whole life. She has been on eating plans provided by a doctor to try to gain weight. When she was pregnant, she prayed that she would keep some of the weight after... and in less than week, she was back to her pre-pregnancy size. As a society, we always see people struggling to lose weight and we tend to forget that there are also people who struggle to GAIN weight. In spite of their efforts, it's just not always possible. Our bodies are determined to be what they want to be, a lot of the time. If your sister has been checked by a doctor and they find nothing wrong, then I guess she is destined to be thin. If she doesn't have a doctor, maybe you could suggest a regular check-up for her, just to be sure that everything is perfectly ok?

Some people are genetically thin, they eat alot of food and never gain at all. So, I wouldn't worry about your sister, maybe this is the case for her.