'Fit Mom' Maria Kang is known for her 'no excuses' policy when it comes to weight loss, but it seems the mother-of-three has changed her outlook after separating from her husband, dealing with depression, and ultimately gaining weight.

The 36-year-old rose to fame in 2013 when she shared a controversial photo of her toned body posed next to her three young sons with the tagline: 'What's Your Excuse?' The image has been dubbed everything from motivational to body shaming, but three years later, Maria has admitted that she has put on weight and is working out less.

Maria took to Instagram to share an unretouched photo of herself modeling a red string bikini as she revealed that she is 10lbs heavier after a tough year.

Fit Mom: Maria Kang took to Instagram on Sunday to share an unretouched photo of herself in red bikini

Feeling great: The mother-of-three explained that she has gained 10lbs since shooting her controversial 'What's your excuse?' photo three years ago

Controversy: The 36-year-old became famous in 2013 when she flaunted her physique in a photo with her three sons, using the tagline: 'What's Your Excuse?'

'I am in no way out of shape, but I am definitely and admittedly hard on myself because I rarely see extra skin, cellulite, muscles or a size greater than a two on a magazine cover,' she wrote.

Maria explained that the image was taken during an impromptu photoshoot with her sister-in-law Jaymi Britten after she ate a doughnut.

'I didn't exercise for four days prior and was tired after a day working and being with my kids. And I am 10lbs up since I shot that "What's Your Excuse" photo! So here I am,' she wrote.

'This is a raw photo with absolutely no retouching, no preparation and no shame. I'm finding my beauty again, I'm discovering my strength again and I'm relearning what it means to be brave, bold and unapologetic about where I am in my life's journey.'

Adversity: Maria explained that she over the past year she has separated from her husband and deal with depression. She is pictured now (left) and in 2013 (right)

Loving her body: Maria proudly showed off her figure in a crop-top over the summer

Maria said that she used to diet 10 to 12 weeks prior to a photoshoot if she wasn't in her 'desired weight range'. Closer to the shoot, she would then amp up her cardio and cut out carbs.

The mom would also prep her clothes, apply facial masks, and give herself a manicure in preparation to have her photo taken.

Maria said she would even try eliminate extra water from her body and shoot in the morning before she ate, a process that has kept her from avoiding photoshoots over the past year.

'In the last several months I've been over-traveling, over-stressed and over "it" as I'm undergoing many life challenges and changes,' she said, admitting that it has been 'over a year' since she has felt 'ready enough' to get in front of the camera again.

Looking great: Maria is pictured at the beach with her three sons in July

Coming clean: The mom admitted that she avoided doing photos shoots over the past year because she never felt like her body was ready to be photographed

'There were constantly events, children, stress and even some depression, that prevented me from following through on my quarterly goals,' she wrote.

'Despite how "unready" I felt, I thought about all the women I encourage to be proud of how far they've come and to celebrate their body at every stage of progression.

Since her rise to online fame, Maria started a No Excuse mom movement, which encourages other moms to start free workout groups around the world, and published her first book, The No More Excuses Diet. Last year, she even released a calendar celebrating mothers of all shapes and sizes.

Maria, who worked off her baby weight after all three of her pregnancies, struggled with bulimia in her 20s before she focused on living a healthier lifestyle.

Transformation: Maria, who struggled with an eating disorder, often shares photos of her body before and after she got healthy

Maria's sister-in-law Jaymi Britten photographed her for the impromptu shoot, which was unretouched

Although she has been accused of fat-shaming in the past, Maria told Cosmopolitan last year year that there are 'definitely permissible excuses' for being out of shape, however, she stood by her message that health needs to be a priority.

'It's just so annoying when I hear excuses,' she added. 'I think that you either want it or you don't. You really have to make that choice, take accountability, and own your actions.'

Maria has been married to former marine David Casler since 2010, however, she revealed on Sunday in an emotional blog post that they separated months ago, and she is struggling with her emotions.

Rise to fame: Maria published her first book, No More Excuses Diet, in 2015

Hard times: Maria and her husband David Casler (pictured) have been married since 2010, but the mom recently revealed that they have been separated for months

'My moods have been volatile, colorful and constantly changing,' she wrote. 'I’m either up or down, angry or ok, upset or calm, tearful or solemn.

'Like my life this past year, I feel like I’m just trying to stay above water, trying to hold things together while breaking slowly apart.'

Maria explained that for a long time she felt 'invisible' in her marriage, and now she wants to find herself again.