A.,
You can easily make sure that your daughter's diet is appropriate for her, without sacrificing your own health goals. Make sure she is driking whole milk, which she should have until she turns two, give her a little bit of cheese at snack time, make her an egg for breakfast, etc. Her dietary need for fat is not large, just a little is all she really needs.
My bigger issue with dieting around your daughter is in passing on body image ideals to her. PLEASE don't talk about dieting in terms of being "fat" or about how you look in front of her. Little girls today start talking about losing weight or needing to go on a diet because they're fat around age four or five. That's abominable, and sets up a lifetime of issues with body image and self esteem. If you need to lose weight, and the discussion about it occurs in front of your daughter, please make sure to talk about eating healthy foods, about making your body fit and strong, etc. Make sure you aren't emphsizing appearance, "look how big my butt looks in these jeans" is a statement you will be shocked to hear when it comes out of her little mouth in a couple of years.