Doctors Michael F. Roizen and Mehmet C. Oz, the authors behind the phenomenally successful guide to the human body You: The Owner’s Manual, now turn their attention to nutrition in You: On a Diet. With their uncanny ability to easily explain the complexities of human biology, the good doctors present a commonsense, science-based diet and fitness plan (deemed waist management ) in their distinctive, lively way.

Roizen and Oz understand just how tough getting and staying in shape can be. When it comes to dieting, trying to whip fat with our weapon of willpower is the food equivalent to holding your breath under water, they write. You can do it for a while, but no matter how psyched up you get, at some point your body your biology forces you to the surface gasping for air. You: On a Diet mixes goofy-fun illustrations, suggested exercises and appealing recipes with in-depth explanations of everything from how your body processes food to the difference between healthy vs. bad fats. Roizen and Oz also uncover the chemistry behind emotional eating. Craving sugar, for example, may signal depression, while reaching for salty foods likely means a major case of stress. Armed with such useful information, the battle of the bulge may become a lot easier.

Actress and yoga enthusiast Mariel Hemingway will always be known as one of the famous descendants of Ernest Hemingway, but she is carving out her own niche as a proponent of healthy living. In Mariel Hemingway’s Healthy Living from the Inside Out, she shares a four-part, 30-day plan that encourages readers to clear the clutter and cut the crap with holistic lifestyle changes in four areas: food, exercise, home and silence.

While she occasionally lapses into Hollywood new-age speak you may or may not be ready to learn to stay present or consider whether your home has negative energy Hemingway offers sensible changes to transform one’s life into one a little less hectic and a little more enjoyable.

Naomi Judd is nothing if not honest. In Naomi’s Guide to Aging Gratefully, she shares her secrets for keeping family close, keeping romance alive and keeping mind and body nimble.

In spelling out her philosophies for living well, she also dishes out a fair amount of Judd family dirt. Daughters Wynonna and Ashley, famous performers in their own right, take a central role in the chapter titled, Children, Grandchildren and Parents, in which Naomi recounts the trio’s now infamous appearance on The Oprah Winfrey Show and wonders, If I say something in the woods and Wy and Ashley aren’t there to hear me, am I still wrong? Still, it’s clear that for Naomi Judd, family will always come first. Judd even keeps a mom line, a phone for her daughters only, which she always answers no matter the time of day. Judd’s joie de vivre spills from every page of homespun wisdom. As she puts it, Shift happens, but her approach to aging makes it sound downright fun.

Since 1995, when he helped Oprah lose 90 pounds and train for a marathon, lifestyle coach Bob Greene has been in the media spotlight. But his crusade to help people lead healthier, fitter lives began years earlier, during his childhood, when Greene would lecture his father on his liberal use of the salt shaker. He went on to study health and exercise physiology in Delaware and Arizona, and was managing the fitness staff in a spa in Telluride, Colorado, when he had his life-changing encounter with the famous TV talk show host. "Oprah and I hit if off right away, although during our first meeting she wouldn’t look me in the eye. Despite her fame and accomplishments, Oprah felt ashamed of her weight," Greene recalls on his website. But the two soon settled into a successful routine. After a lifetime of gaining and losing large amounts of weight, Oprah reached her goal weight with Greene’s help and she’s stayed at a healthy weight for the past 10 years. He’s been a part of her life for those 10 years as well, making appearances on The Oprah Winfrey Show, contributing to O magazine and even helping Oprah find the perfect Hawaiian vacation home.

In his new book, The Best Life Diet, Greene expands on the fitness philosophy he’s developed over his long career (and in his other books, including Total Body Makeover and Get With the Program!). He believes that making a commitment to gradually increase your activity level and decrease your food intake (and winnow unhealthy foods from your daily diet) is the only way to lose weight and keep it off. He discusses the reasons people overeat, including the emotional ones. For Oprah, becoming aware of and dealing with her habit of burying her emotions under plates of food was the most critical component, Greene says. The Best Life Diet suggests that if you’re in the same boat, recognizing that fact will make it easier to avoid those destructive habits.

"After working one-on-one with many clients and talking to thousands of people through the years, I think I can say with some authority that the fast and furious approach to weight loss is also the fastest route to failure," writes Greene, and his slow-but-steady strategy is both simple and effective. In Phase One, which lasts four weeks, you raise your level of activity (which is as easy as doubling the number of steps you take each day if you’re totally inactive, and exercising three times a week if you’re somewhat active), change the way you eat (three healthy meals a day plus at least one snack) and take a multivitamin. Phases Two and Three each intensify the activity level, and increase food intake to three meals and two snacks per day. Ultimately, if you skip meals, you won’t save calories, cautions Greene, since skipping meals decreases your metabolism and increases the odds that you’ll overeat when you finally get a chance at food.

The Best Life Diet includes recipes for delicious meals and snacks that won’t make you feel deprived, like Salmon and Spinach Frittata, Black Bean Chipotle Burgers, Vanilla Caramel Truffle Lattes and Hazelnut Biscotti. More recipes, exercise routines and advice can be found on the book’s companion website, thebestlife.com. To help you make smarter decisions at the supermarket, Greene has joined forces with several major food manufacturers to place the Best Life Diet seal of approval (shown on the upper right-hand corner of his book’s cover) on products he believes meet the needs of anyone trying to lose weight and eat healthfully. Though Greene is an understanding, encouraging and empathetic guide through the wilds of weight loss, he’s also adamant that his followers adhere to the high standards he sets for them. " One thing you’ll never hear from me is that making changes in your life is easy. . . . Each step you take toward your weight-loss goal is a gift you give yourself." That about sums it up.