What Is the World's 'Best Diet'?

There sure are a great many diets. Low-carb, low-fat, vegan, raw, paleo, gluten-free, and on, and on. Which one should you choose? Is there one diet that's been proven to be head-and-shoulders better than others for weight management? If so, how might you figure out which one it is?

Looking to bookstores won't be terrifically helpful, as it will likely take time to wade through the 124,000 or so diet titles that currently populate shelves. Looking to the internet may be confusing, too, as you'll immediately encounter duelling nutritional gurus--each one loudly discrediting the next. Looking to your friends will only get you as far as where they're currently at, since they'll undoubtedly champion whatever it is they're currently trying themselves.

So how about looking to the scientific literature, will that shed light on things?

Unfortunately not.

The fact of the matter is that despite the $60 billion a year North American weight-loss industry; the incredible desire and motivation of folks trying to lose; and the medical researchers that have published literally tens of thousands of dueling articles on diets and obesity, as far as weight management goes, there is no single "best diet." That conclusion might lead a person to bemoan the futility of dieting, but maybe the glass is actually half full.

What if there were many best diets? What if part of society's struggle to lose weight is the pervasive notion that there's only one right way to go? Could our belief that dietary rigidity, suffering, and restriction are the ingredients to success in fact be distracting us from the truth--that there are innumerable roads to success?

Here the scientific literature is helpful. Looking at an ongoing 18-year-old research project called the National Weight Control Registry--a 10,000-plus member registry of adults who've lost more than 60 pounds and kept them off for 5.5 years--reveals that there are no absolutes to success. Registrants have lost weight every which way there is, from fast to slow, from low-carb to low-fat, both on their own and with programmatic help. And while they do share some habits in common--many eat breakfast and limit TV time--still 22 percent of them skip breakfast and 48 percent watch more than 10 hours of TV a week. Clearly there are different dietary and lifestyle strokes for different folks.

Carefully controlled laboratory studies echo the registry's findings. One such study conducted by Columbia University's Rudy Leibel and colleagues in 1992 followed the impact that diets differing in fat and carbohydrate content had on body weight. What they found was that if they held calories constant, participants' weight remained constant, even in the face of diets that ranged from 15 to 80 percent carbohydrate and from 0 to 70 percent fat. Translation: Irrespective of diet type--whether low-carb, or high-carb; low-fat, or high-fat--in a perfectly controlled laboratory environment, weight stays stable when calories are fixed. Of course life's not a perfectly controlled laboratory environment, and what leaves one person happily satisfied will leave another wanting.

So what does all this mean?

Your best diet is the one that keeps your calories reduced, your hunger at bay, your cravings controlled, and provides you with a regimen that isn't merely one you can tolerate, but rather one you can honestly enjoy. The reason there are so many diet books and gurus out there is that there truly isn't one right way to go.

So feel free to wade through the bookshelves, sample from the gurus, and poll your best friends. They may offer up some really wonderful suggestions and strategies. But ultimately, never let yourself get cornered into a dietary pigeonhole. If one approach isn't working for you, try to identify what it is you'd need to tweak in order to like it. And when it comes to those real-life moments where what you want doesn't fit with your chosen approach, try to remember that perhaps it's that very inflexibility that's led you to give up altogether in the past.

Live the healthiest life that you can enjoy, not the healthiest life that you can tolerate.

Hungry for more? Write to eatandrun@usnews.com with your questions, concerns, and feedback.

Yoni Freedhoff, MD, is an assistant professor of family medicine at the University of Ottawa, where he's the founder and medical director of the Bariatric Medical Institute--dedicated to non-surgical weight management since 2004. Dr. Freedhoff sounds off daily on his award-winning blog, Weighty Matters, and is also easily reachable on Twitter. Look for Dr. Freedhoff's book on the fallacies and future of modern-day dieting to be published by Simon & Schuster's Free Press in spring of 2013.