Our pediatrician, Dr. William Sears, noted that if she was this weight with getting formula or cows milk and / or bad nutrition (cakes, candy, soda chips etc) perhaps then it would be a concern but because bulk of her nutrition is nursing, her body will use up all the healthy fats stored because they're from breastmilk which is stored differently than normal fat coming from excessive eating or bad nutrition. (attachmentparenting.org)
So mealtime is more about her getting used to the act of eating and learning the tastes and textures of foods than it is about providing the bulk of her nutrition. (parents.com)
But, he still gets the bulk of his nutrition from breastfeeding, so I would say he breast feeds a lot. (pregnancymagazine.com)