Of course, the American Academy of Pediatrics and the WHO recommend exclusive breastfeeding for the first 4-6 months. The closer to 6 months you wait, the better because milk gives everything a baby needs until sometime between 6 and 12 months. Exclusive breastfeeding means NOTHING but breastmilk. No water. No formula (it may as well be adult food). No rice cereal. Medicines intended for babies are ok.
If your baby can't sit up by him or herself, it's best to wait. I know that the Gerber baby food containers have foods they say are appropriate for the "Supported Sitter" but sitting up is an important milestone to wait for. Gerber just wants to sell baby food to eager parents and grandparents. If the baby does not lean toward the spoon and look interested (which probably won't happen if she can't sit up) then she's not ready for food.
So how much food does the 6 month old need? The WHO says that 6-8 month olds should have 2-3 meals per day. I've heard from other sources that starting with 1 and increasing to 2 at this age is fine. WHO says that 6-8 month olds eat about 2-3 Tablespoons of food per meal at first, but will increase to 1/2 of a 250mL cup of total food per meal. In the US, our "cup" is 236mL, so a little more than 1/2 cup. But, the amount of breastmilk intake should not decrease. WHO also says that it's ok to offer small nutritious snacks at this stage.
Ewan is almost 8 months and I can only get him to eat a few tablespoons of food. He's teething currently, so that is interfering with his eating some days, possibly. He has also started to be pickier than he was at first. He used to eat pretty much anything I gave him, but now he won't open his mouth for certain things. He will open a little to taste what's on the spoon and if he doesn't like it, he won't accept a full bite.
I've been consulting WholesomeBabyFood.com for their advice, as well. They have recipes, sample menus and nutrition information. Their page on 6-8 month olds has similar information as the WHO page. They also have a page that discusses how to read your baby's cues and know if your baby is eating enough.
For breastfed babies 9-11 months, the WHO says that they should eat 3-4 meals per day and eat 1/2 of a 250mL cup per meal, and 1-2 snacks may be offered.
For breastfed babies 1-2 years old, the WHO says 3-4 meals plus 1-2 snacks, and the baby should eat a full 250mL cup of food per meal.
The WHO page does not say at what point breastmilk intake should decrease, and they recommend continued breastfeeding to 2 years. Nancy Mohrbacher says in Breastfeeding Made Simple
that by 4 weeks, babies begin drinking 25-35 ounces (740-1035mL) of milk per day and that this will continue for the first 6 months, when after that the milk intake will decrease as food intake increases. I still practice on-demand nursing with Ewan, but he has fallen into more of a routine than he had before he reached 6 months. I talk about that in this previous post.Many American pediatricians suggest weaning at 1 year and replacing with cow's milk, but why? I'm not sure. Mom's milk is the best nutrition, so why switch to cow's milk when the baby's brain is still developing and still needs optimum nutrition? Ewan was cow's milk intolerant as a newborn so I may not introduce cow's milk products until after 2 years anyway. I have given him sheep's milk yogurt mixed into other things such as banana or beans. (Try plain yogurt and black beans! It's really good!)
The best advice I have seen is:
-Nurse your baby often (to ensure adequate milk intake)
-Let him or her eat as much complementary food as he or she will eat (hunger should dictate food intake)
-Feed your baby at family meal times (because babies love to mimic others)