bacon and a bowl of beans. not all grains are created equal. there's a difference between white bread and wheat bread. so that is going to be a challenge even with this one is to tell americans what protein is good and bad and what grains are good and bad. >> i mean, i think of it as a symbol might help that half that plate has to be fruit and vegetables. that's a lot of fruits and vegetables. i think our life has to be reordered around it, our grocery stores, how we eat. half a plate of fruit and vegetables is a lot. >> everybody recognizes a symbol is not going to do it. you can show this to schoolchildren and it's not going to make a difference unless other things happen to make that plate half fruits and vegetables. >> you're right about that. but we can try. elizabeth cohen, thank you very much for that. and for all the latest news in health and nutrition, go to cnn.com/health. american astronaut katie coleman is back home after spending 159 days in space. she's going to tell us what it's