Hi,
that sounds fine- if not great really! At about 4 months they're still supposed to be taking at least 18-20oz milk a day so that's the minimum. Mel was a very hungry baby and at 4 weeks he was taking about 34oz of SMA Gold which decreased when we switched to the White (phew becuase his weight was going through the roof!). We had to start weaning him at the end of 17 weeks too as he was desperate for food and the amount of milk went down quite a bit. I found that he took more and more pureed veggies until the magical 6 months when I introduced meat at lunchtime and the amount of veggies went down quite a bit. I think that solid food stays in the tum more and protein stays longer than veggies. Mel has always been a large baby- at 17 weeks he was 17lbs (just below 91% centile) but I had him weighed yesterday and he was 18lb 12oz (at 26 weeks) which was just around the 75% centile so he's actually slowed down the weight gain since solids which is amazing as I was worried that he was wolfing it down and would be off the chart!
As for the homemade I started off with pureed steamed vegetables as they're not too rich for them (and it's lots cheaper!). You're supposed to avoid things with gluten (wheat, oats, pasta etc) until 6 months and also meat and other proteins like lentils and cheese etc. When he started to obviously need more than just veggies but it was still too early for the meat I increased the amounts of baby rice or instant baby mash potato that I gave him with the veggies so that he had the bulkier carbohydrate to fill him up. Basically before 6 months he had tried potato, carrot, parsnip, swede, sweet potato, banana, pear, apple, apricot, avocado, baby rice, broccoli, cauliflower and squash.
Hope this helps
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