I have had to 'diet' to a degree throughout this pregnancy I was diagnosed with gestational diabetes and am insulin dependent. I have to watch my sugar intake and eat a low GI diet. With only 4 weeks to go I am 2kgs lighter than I was at the beginning of my pregnancy and I even have some pre preg clothes that are too loose on me. So I have definitely lost weight. Obviously it has all been done under medical supervision, but it is possible and it can be done safely. i guess the key is just to get lots of healthy food in and avoid anything high in sugar/fat.