You see this response often on weight loss or diet forums.
Someone starts with “I lost 87 pounds in 3 weeks, but my friends are telling me I’m losing too fast” (exaggerated for the point).
The automatic response is “Oh they’re just jealous”.
A lot of forum posters don’t consider that this persons friend(s) may be genuinely concerned for their well being.
When someone loses a lot of weight very quickly, their body and face may go through some drastic changes that, for all appearances, may make them look ill.
Saggy skin, sallow complexion, sometimes serious acne outbreaks, hair loss, etc.
Perhaps this person has had an eating disorder in the past, or has serious health issues.
A real friend has every right to be concerned if they see someone that they care about looking like they may have contracted some rare disease.
They’re not being un-supportive, as the poster would have you believe, they may be honestly concerned, as a friend.
People rarely divulge all the details on a forum, they just post what’s going to get them the most attention, consolation and back patting.
Keep in mind that, other than a few rare instances, the people posting and responding are strangers who don’t know the people they’re engaging on that site, except what that person has decided to tell them.
So don’t automatically assume the person is jealous, they may be a real life friend who has real life concerns.