I hate to say it -- as much as I love Gwamma -- but she is woefully misinformed abotu breastmilk. In fact, her statement is utter nonsense and absolutely unsupported by major health organizations and science.
Breastmilk is designed to be the sole food of human infants for up to 8 years. I know that it seems strange in our culture to think of an "8 yr old* as an infant, but based on our fellow primates and similar research, our breast milk can sustain children for a long time. Natural Age for Weaning (PhD research).
The WHO recommends breast feeding children for at least two years -- and in developing nations, even longer. The reason being is because the food and water supplies in developing nations are not as sustainable as in developed nations. The body will filter everything and *provide the best nutrition* for the children, providing them the opportunity to thrive and far less exposure to disease in water or food. It also provides human growth hormone, immunity antibodies (similar to vaccination theory) from the mother, and overall is the best nutrition for infants.
The AAP recommends *at least one year* of breast milk, and the American Academy of Family Physicians recommends going to at least 2 years of age because it increases health and immune function in the infant -- and they recommend "longer so long as it is mutually desired."
At the very least, mothers can provide the required nutrition for up to two years -- with or without food. (source)
It might also be helpful to understand how milk is developed in our bodies -- and that the nutritional needs of the infant change over time, and so, therefore does our milk. So long as the lactating mother is healthy, consuming enough calories and nutrition (including support like herbal teas), and getting the proper stimulation (pump or nursling), and has adequate supply overall, then the milk will meet the nutritional needs of the child. (kellymom.com)
Another cue is teeth. Babies generally do not have teeth until they are around a year old, at which time they will start taking food for nutrition -- while still relying on breastmilk to fill any gaps in nutrition, as well as provide human growth hormone, immune antibodies (from the mother -- works like vaccines), and the additional fats that their bodies and brains need to grow. This is why the baby-lead weaning movement focuses on "play/experiment" with food starting between 8-10 months, and most will then start to actually eat after they get *teeth* -- between 1 yr and 1.5 years. (baby-led weaning)
I know that a lot of people pressure others to feed their baby a lot of food starting at 6 months -- because of fears around breastmilk not providing, etc. But breast milk is amazingly adaptable.
I really wish people would stop giving outdated advice about breast milk. *le sigh*