 Health at 20 leads to real health consequences at 40. I'm Cooper Lawrence, health and wellness expert, and this is all well and good. Just last week, scientists discovered that a healthy diet at 40 means a healthy life at 70. Now comes a study finding that getting to a healthy 40 isn't a given. So many people in their 20s assume that since they're young, they'll bounce back. Researchers at UC San Francisco found that's not true.