Source: Bang Showbiz NewsKelly Clarkson' has revealed her weight loss secret is falling in love and has shed 18 pounds since meeting her fiance Brandon Blackstock last year.The curvy 'Stronger' singer has revealed she lost 18 pounds after meeting her fiance Brandon Blackstock - who popped the question to her last month after just nine months of dating - because she wanted to look good for him.The 30-year-old popstar told the February issue of Cosmopolitan magazine: "I lost 18 pounds. And I think that happens when you fall in love or date someone. If I'm going to be messing around, I gotta look good."There's not a fad diet. I was working with a trainer, and she said, 'You'd be amazed the amount of weight you can drop by halving your portions. I know it sounds crazy, but do it for two weeks and watch what happens.' I just cut back my portions, I stopped eating late at night, and I work out a little more than I used to, and I literally dropped 18 pounds in a month. I think it happens when you get really busy. But when I'm on my off-time - girl, those 18 might come back."The newly engaged starlet also insisted that she despite feeling the pressure to slim down she wasn't willing to go on a crash diet.She said: "I'm not willing to do that. I'm willing to work a little bit because I want to be a healthy individual - which I always have been. I've put on weight, but that's just what I'm happy with at that moment."Brandon and I both have bikes on the back of the bus, and we both love the outdoors. Once your lifestyle becomes more active, obviously you drop weight."