There are various articles online quoting studies (or even loosely referring to "studies" without reference) claiming you can only gain fat cells but not loose them. Some examples include Calorielab.com:
Fat Cells Shrink, But Don’t Die
As well as CNN.com:
"If anyone of us overeats long and hard enough, we can increase the number of fat cells in our body," Fried said. "When we lose weight, we don't lose the number of fat cells."
Earlier in the article: "Susan Fried, director of the Boston Obesity and Nutrition Research Center at the Boston University School of Medicine"
CNN does mention one way to actually get rid of the cells:
Liposuction can remove fat cells
Even after marked weight loss, the body never loses adipocytes.
Now, to end with a question: are these claims true that you can not loose fat cells with any kind of lifestyle change (diet, exercise, etc), and only with invasive (e.g. surgical) methods?