Book excerpt: "We have proof that aging doesn't have to be a downward slope. There's your chronological age-what the calendar says-and then there's your biological age, which is a measure of how well your body and brain are holding up for your chronological age. And there's mounting evidence that a healthy lifestyle can actually lower your biological age from the inside out. These healthy lifestyle changes-to your diet, exercise, and sleep habits and to how your deal with stress-are totally accessible to anyone and bring amazing results. How do we know? We combed the latest science and consulted with a dream team of advisors in health, fitness, nutrition and beauty to roll our findings into a simple Younger in 8 Weeks Plan. Then we tested it on 21 women ages 36 to 66 who'd been struggling with weight gain, lack of energy, loss of luster, and other common age-related issues."-