Babies are unique in their eating style and they know how to grow and develop. Trust them to tell you how much they need to eat. It is your job to love them and feed them. (1)
That is why we encourage you to feed your baby on demand. At three weeks of age, if your baby has probably had a least one weight check. If they are gaining weight, you know that you can trust them to let you know when they need to eat. If they are not gaining weight as expected, then you will work with your healthcare provider to find out why. Please seek the help of someone knowledgeable about breastfeeding to help you as well. See Where to Find Breastfeeding Help.
It is still normal for most babies to eat 8 or more times in 24 hours when they are three weeks old. A few will breastfeed less than 8 times per day, but the key is if they continue to gain weight.
- Satter, E, Child of Mine: Feeding With Love and Good Sense, 2000, Palo Alto, CA, Bull Publishing, pp 118-129.