I have a friend who is suffering from obesity, do you know what that is? 
I do Obesity is a medical condition in which excess body fat  ccumlate
Ohh okay I see, is there anyway to reduce that excess body fat? 
i have heard People are generally considered obese when their body mass index (BMI), a measurement obtained by dividing a person's weight by the square of the person's height,
Okay I see, that is interesting to note, I am not sure what her BMI is, but she told me she has been diagnosed with obesity.  Can you tell me more about it? 
you should know Obesity increases the likelihood of various diseases and conditions,
I have heard about that before, what types of diseases and conditions does it increase? 
yeah and  On average, obese people have a greater energy expenditure than a healthy person