I love everything about this book. Even though I'm in my early thirties, and it is clearly addressed to a post-40 audience, we all deserve to know a wise, health-conscious elder woman, who tells us what to change in our lives today to live a healthier, painless (or less painful), and more content life in 10, 20, 30, maybe 40 years' time. And while I do have a mother and a friend who subtly educate me on these matters, sometimes a book - an all-round guide - is what it takes to change a habit, buy salad greens more often, and consciously try to seek pleasure and peace. 
This is a perfect gift to a woman you love, or to yourself. It guides you through seasons giving practical pointers and reminders when needed; if you know 
Lit from Within, consider 
Younger by the Day to be an advanced course.