The Atonement star admits she struggles to find outfits for red-carpet events as designers refuse to lend her garments because she doesn't fit their sample size U.K. 8 (U.S. size 6).
Garai fears the links between film and fashion have led to a blurring of boundaries and there is now little distinction between models and actresses.
She tells British magazine the Radio Times, ""My weight was a very big issue when I started. I was then - and am now - a very normal (U.K.) size 10 (U.S. 8). But that's not acceptable.
""It's partly because fashion, film and television have become so interdependent. Increasingly, it's actresses doing the big fashion advertising campaigns and now there's no distinction between actresses and models.
""There's no way I could ring up a company that was lending me a red-carpet dress and say, 'Do you have it in a 10?' Because all the press samples are an eight. If you want the profile, you have to lose the weight.
""It's difficult because if I refuse to do any magazines at all, my work, I think, would suffer in a very immediate way. But when I appear in these magazines, I know I'm being 'trimmed'. I'm being airbrushed a lot.""