This chapter examines the best evidence for weight loss, chronic disease prevention, and longevity. It shares science-based consensus and dietary advice on how to lose weight, prevent a heart attack, control appetite, and live longer, highlighting the role of a plant-based diet.  It defines healthy and sustainable eating, including reducing ultra-processed foods (UPFs), refined grains, sugar, and salt; increasing whole grains, beans, nuts, and legumes; and limiting (or avoiding) meat and dairy.  It discusses weight loss diets (Paleo, high-protein, WW, low-fat, Whole Foods Plant Based [WFPB], meal replacements), reminding that appetite and calories are key—alongside finding a diet you can stick to. It explores the five Blue Zones, the world’s longest-lived populations who consume diverse plant-based diets within their unique culinary traditions.  The chapter closes on caloric restriction (and calorie-restriction mimetics) in longevity and considers scientific and technological innovations like digital upload, artificial intelligence—or even a “god pill.”