As someone else pointed out, fruit IS healthy, but can be loaded with natural sugars, which is still a carb.....
Check out the Reader's Digest Diet... it focuses on proteins, veggies, complex carbs, and dairy. When I was following it, I lost almost 20 lbs in just a few months... however, when I stopped following the 3rd step of it, and added the carbs back in, I did gain most of that back... I still am down about 8 lbs from my starting point, however, so I still see that diet as a positive.
There are a LOT of very yummy recipes on the diet that I still use... I just really need to cut out the processed carbs and I will do better.
As you pointed out, you do need extra calories for the breastmilk, but at 16 months, she is getting a lot of her calories from regular food.
As far as weaning... how often do you still bf her? Start by cutting out what seems to be the "least desired" bf time..... (that depends on how often/when you still bf her)... try to distract her with something else, and offer a sippy cup if she is thirsty.
Gradually cut out the different nursing times, and it will happen.