"Body-shaming in all forms is inexcusable": Isabelle Cornish shuts down her critics.

Unfortunately, we’ve been seeing a lot of body shaming happening to high-profile women this year.

Kelly Clarkson, Pink, Selena Gomez and Chrissy Swan have been targeted by nasty “fat” insults in recent months, and all three of them responded with absolute class and good humour.

RELATED: “Why I’m happy with my size 16 body.”

On the other side of the coin, in April Giuliana Rancic addressed the ongoing criticism her slender frame cops from the public, stating, “I’m sorry that some people think I’m disgustingly skinny, as they put it, but there’s nothing I can do… I want to look fit and beautiful and sexy, and I can’t.”

Now, Australian actress and model Isabelle Cornish has condemned her body shamers on Instagram, Only to receive instant backlash.

The Puberty Blues star, who is soon launching her own health and fitness website, is regularly criticised by her followers for being ‘too thin’. Last week, Cornish — yes, she’s Abbie’s little sister — finally hit back by sharing a photo of herself at the beach (below) and a firm message for her detractors.

"No one should feel like their body isn't 'good enough'. Everyone is different. There is no perfect one size for all. I may be smaller than other people but I am fit and healthy! I work out, I am very athletic and I nourish my body with a good diet," the 20-year-old wrote.

RELATED: “I struggled with my body. So I did a lingerie shoot.”

"Body-shaming in all forms is inexcusable. Stop comparing yourself to others and spread love and confidence not negative body image messages!"

Evidently, this message still wasn't good enough for many of her 177,000 followers. (Post continues after gallery.)

While some responded with supportive, fist-pumping comments, others remained critical, often framing it as 'concern' for the actress' health. Here's just a sample of their comments:

Too fat, too skinny, too curvy, not enough curves — us women just can't catch a break, can we?

What these people seem to be forgetting is that they're critiquing the appearance of a woman who is just 20 years old. Cornish is only just out of her teen years. Do you remember how susceptible you were to other people's opinions of you at that age? Maybe you still are.

RELATED: Rachael Taylor fell for this ludicrous Hollywood diet. And she regrets it.

The thing is, body shaming of any form can have a hugely damaging effect on a woman's self-esteem and body image, regardless of age and size. And no, even if they supposedly come from a place of 'concern about her health', critical comments about a woman's body are not helpful in any way. In fact, they're damaging.

“Commenting on anybody’s weight, whether it’s because they are ‘too skinny’ or ‘too fat’ is very unhelpful. This sort of body-policing only serves to reinforce the idea that a woman’s self-worth is directly related to her appearance,” says clinical psychologist Olivia Patrick.

Even though women like Isabelle Cornish and Kelly Clarkson are famous, constantly in the public eye and have thousands of social media followers to their name, this doesn't give any of us the right to be cruel about their appearance. In fact, doing so only further ingrains our own body concerns and negative feelings.

“Other people’s bodies are none of our business, and focusing and commenting on other people’s appearances will only keep us placing undue importance on our own weight,” Dr Patrick says.

RELATED: Why Jennifer Lopez’s #BeTheGirl weight loss challenge is disappointing.

To the Internet heroes who constantly feel the need to bring women down, here's some advice for you: log off Instagram, put down your phone, go outside in the fresh air and get some bloody perspective.

Have you ever been body shamed? How did you respond?