Tea and coffee prevent your body from absorbing iron properly. Calcium is essential for healthy bones. It is therefore vital that your diet includes the correct amount of calcium whilst you are breastfeeding as babies bones grow rapidly. Baby will take what calcium it needs at the expense of your own bone density if your diet is deficient in calcium. This generally affects menopausal women but by putting in the work now you will be protecting the future health of your bones.
Activity is also important for bone strength, and a little sunlight.
Vitamin D is made by the action of sunlight on the skin and is needed for the absorption of calcium. But don t sun bathe, being outside is enough. Eating sensibly will benefit both you and baby. Your fluid intake will automatically increase, let your thirst guide you and drink plenty of water. These exercises are very important, as they will help you to target and exercise specific muscle groups, and are aimed at getting you back into shape.