8 month old breast fed son has only gained 11 oz in 2 months?

So, about breastfed babies - they gain rapidly in their first 6 months or so, often faster then formula fed babies and then slow down much more then formula fed babies. In addition babies that are sitting up and starting to move also gain slower.

No more formula, and forget trying to get him to take more from a bottle (breast milk is 22 cal/oz vs. 21/oz for formula), instead concentrate on higher calories baby foods - they exist. Some 4oz jars are only 40cal but you can find some that are 100-110calories (Beechnut), and add whole milk baby yogurt (100 calories for 4oz). Oh, and rice cereal alone is stupid - mix with puree and a dab of olive oil. He can also have shredded cheese, cooked egg yolks. That is if you are really worried but I would not be, as long as he is getting longer he's fine.

My daughter was about 16 1/2 lbs at her 6 month check up and at her 9 month check up she was just over 15 1/2 lbs and didn't get that much longer. My doctor wasn't conserved at all. She is more active now with crawling and cruising. She is exclusively breastfed has never really accepted baby food and eats very little table food. She has never been sick. Our doctor just said that babies go through growth spurts at different times and this was not a time for her. I know she has gained weight since (she is now 10 months) but probably not a whole lot. I would say that as long as your son is healthy don't worry about it too much. He is gaining weight and is going to be burning more calories now that he is getting to be more active.

Weight gain commonly slows in the second half of the first year. AND babies continue to gain weight somewhat erratically, having growth spurts when they gain a lot, and then gaining little or nothing in between.

Your baby's weight gain is just fine. He'll likely have a growth spurt in a month or two and make up for any shortfall.

I WOULD stop thickening his bottles with extra formula. If you must feed formula you need to mix it EXACTLY as directed on the label, which means mixing powdered formula with water, NOT breastmilk.

You might also cut back a little on the solids. 12 ounces of solid foods is on the high end at this age, and he's probably better off getting a little more breastmilk.

"Adding formula to his breastmilk was suggested by the dr"

!?!?!

You really want a new physician; this is dreadful advice -- your breastfed son does not need to be exposed to the risks of formula, and adding undiluted formula to breast milk is absolutely not how one makes up milk feeds for infants and it is shocking and bizarre that a doctor would be unclear on how that sort of thing works.

"Should I be alarmed he isn't gaining weight very fast?"

No.

Have a read through the weight gain pages on http://kellymom.com/ and get a copy of Dr Jack Newman's book, which has an excellent chapter on ditto.

"Our next dr appt isn't until his 9 month check up."

Good; that's a full month to find one with a clue.

I don't know but my son is 6 months and he weighs 19 pounds.... and I only breastfeed him nothing else yet... I will start on solids soon... and he feeds on demand... good luck!