The 25-year-old retired swimmer has suffered online bullying about her appearance.
She broke down in tears on I'm A Celebrity... Get Me Out Of Here! last year as she compared herself to model Amy Willerton.
But speaking for the first time about her appearance since reportedly undergoing surgery, she said: "I'm definitely happier with how I look now.
"But I wouldn't necessarily say happy. I think you still always see the same thing when you look in the mirror.
"A lot of people tell me that you get more comfortable with yourself with age and obviously I've still got a lot of growing up to do.
"But I will never have this figure that's big-boobed and tiny waist and curvaceous bum.
"I know I have got slightly bigger shoulders than some people and an average cup size, that's not going to change."
Adlington, from Stockport, Greater Manchester, has refused to confirm or deny suggestions that she has had surgery on her nose.
"If somebody else wants to know (that), well tough luck," she told the Mail on Sunday.
"It's my life. Loads of women have loads of things that they do - like a Kim Kardashian or whatever - but I just think if you open yourself up in that way, there's a lot more that happens.
"I've never opened the door in that way. I never set out to be in the spotlight. I've fallen into it by doing something that I love, that is my passion."
Adlington, who won two gold medals at the Beijing Olympics in 2008 and two bronze medals in London four years later, said she has blocked 2,000 - 4,000 abusive people on Twitter.
Her fiance, swimmer Harry Needs, encourages her not to check the social network site when she is at home.
She said: "I sit there at eight o'clock at night and Harry's saying, 'Bec, why are you checking Twitter? You're allowing them into our home'.
"I'd never thought of it that way. You're sat there in your home, which is your comfort zone, and yet you're reading comments from other people and allowing them in.
"I thought 'yes, you're right. Why am I doing this?' I've tried to stop it now... although I do it if Harry's out."