Brittany Snow used to have a ''big issue'' with exercise and eating.

The 31-year-old actress has admitted she used to strive to look like slender models she would see on the front of fitness magazines because she felt that was the epitome of ''happiness'', and the 'Pitch Perfect' star has admitted she used to feel ''frustrated'' when she did not drop weight.

Speaking to Shape magazine about her body and her battle with anorexia, the star said: ''I had a big issue with working out and dieting. I wanted to be like the girls I saw in fitness magazines so badly. I thought that was the ideal of happiness.

''I used to be frustrated by my body type as a kid. I had muscles without trying and failed when I attempted to lose weight.''

But it wasn't until Brittany hit the 30 milestone she changed her ways because she wanted to put her ''health and happiness'' first.

She explained: ''When I turned 30, I looked at my life and realized that I'd always been on a diet and working out to be the size of a model. I thought, I'm 5'3″, and I inherited my mom's beautiful muscular body -- it's just not going to happen.

''I began eating well to take care of myself -- I'm almost 100 per cent vegan, and I'm off dairy and gluten. I realised that my health and happiness were way more important than being at the gym all the time.''

And Brittany has now embraced her athletic body shape.

She said: ''It's strong not only physically, but also emotionally. Now I've come to appreciate the fact that I'm an athlete.''

The 'John Tucker Must Die' beauty thinks social media is partly to blame for negatively impacting on people's self-esteem as she believes people look on the online platforms and ''compare'' themselves to others.

She explained: ''I think that as a society we're always looking to social media to compare ourselves with how other people look and eat. I put Instagram and Twitter in a separate category in my phone, so I don't check them all the time and am not constantly aware of what other people are doing. I think people use social media to compare themselves with others too much, and it has really negative effects on the psyche.''