A popular fitness blogger tells Fox News she’s thrilled at the response of a recent post in which she called out a commenter who tried to shame her for having smaller breasts.

It all started about a week ago, when Kelsey Heenan – a certified fitness and nutrition coach and the founder of HIIT Max – got a comment on one of her recent workout videos that simply read, “But where are your boobs?”

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Heenan shared the story to Instagram a few days later, firing back with a response that her followers absolutely loved.

"My initial reaction: 'You should probably stop looking for them… They were never here to begin with,'” she wrote.

But rather than lash out, or chastise the commenter, Heenan used the remainder of the post to urge her followers to remain focused and positive, even in the face of negative remarks.

“There will always be people out there that are going to try and bring you down on your journey,” Heenan wrote. “They are going to be negative. They will hate on what you’re doing. They will even make comments about YOUR body… Honestly, let it go (as hard as that can be sometimes). How your body looks is your business and no one else’s.

“As long as you are happy and healthy… Do you,” she added.

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Heenan later told Fox News she wanted her followers to celebrate their bodies and not get discouraged by comparing themselves to others — or listening to anyone who insists on comparing one person to the next.

“It’s important to remind people that perfection doesn’t exist,” she said. “It’s easy to get caught up in comparison, but we can all be great and completely different at the same time.”

Heenan’s followers loved the heartfelt response, with many praising her, and her message, in the comments.

“You look great,” one commenter wrote. “They’re just jealous.”

“I agree with you Kelsey!! As long as you're happy with yourself, that's all that matters!” said another.

“You are amazing, inspiring and beautiful!” another user added.

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Heenan, who shares her tips and inspiration at The Daily Kelsey, says she is thankful for how her Instagram post was received.

"I’ve received an incredibly positive response to the post,” she tells Fox News. “And I am thankful to use my platform to encourage others.”