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You started out with good intentions-you just wanted to lose weight, feel better, or eat cleaner. But now you're preaching the gospel of Paleo, spending weekends searching for low-fat diet studies to debunk, and hurling Twitter insults at former friends who dare to eat wheat.

What happened? Somewhere along the way, your nutrition program brainwashed you, suggests author, nutritionist, and coach Matt Fitzgerald. In his new book Diet Cults: The Surprising Fallacy at the Core of Nutrition Fads and a Guide to Healthy Eating for the Rest of Us, Fitzgerald outlines exactly how modern diets have come to resemble spiritual movements.

And he's not alone in that assessment. "People have elevated dieting to religious zealotry," says Yoni Freedhoff, M.D., a weight-loss physician and author of The Diet Fix: Why Diets Fail and How to Make Yours Work.

It's not hard to see why. Throughout history, what we eat has helped form our personal and cultural identity, Fitzgerald points out. And in a world that makes it easy to binge and pack on pounds, a dieting community can offer support and motivation to buck the trend.

Still, indoctrination comes at a cost. For one thing, you risk alienating your friends and family members who aren't on board. What's more, putting all your faith in a particular plan can blind you to whether it's actually working for you, physically and psychologically, Freedhoff says. In his book, Fitzgerald describes an alternative, more skeptical path to healthy eating. How do you know if you've joined a diet cult? [Tweet this!]

Diet Cult Red Flags

1. You call it by name. From Atkins to Mediterranean to Zone, every diet cult has a moniker, Fitzgerald says. In some cases (but not always) it also has a guru, or a leader who spearheads and promotes it.

2. You're forbidden to eat certain foods. Diet cults tend to ban some items or food groups entirely. Usually, research doesn't really support their rules, Fitzgerald says.

3. You live in fear of cheating. These clans gain new followers by convincing people they're killing themselves with each bite of steak or sugar. "It becomes sinning against your dietary god if you slip," Freedhoff says.

4. Other diets personally offend you. "Each one claims to be ‘the best' diet-and deems all the other diets inferior," says Fitzgerald. You may start thinking, "This is the one true way to eat for optimum health," he adds. (That's despite the fact that people worldwide thrive on a wide variety of eating plans.) If you find yourself angry when someone chooses to follow a different path, "there's something wrong with what you're doing," Freedhoff says.

Break Free!

1. Redefine success. Besides the number on the scale, keep a log of what you eat, your cravings, your mood, and how deprived you feel, Freedhoff recommends. Don't judge yourself for these emotions (or let others in the group do it for you). If you're shedding pounds but starving and miserable, chances are you need to modify your approach.

2. Bend the rules. If you do find you're unhappy, consider changes you can make to help you stick to your plan long-term. Though some evangelists will argue with you, you actually can eat mostly South Beach but add some whole grains, or balance out a plant-based diet with the occasional chicken dish. Freedhoff explains common ways to adjust many popular plans in The Diet Fix.

3. Practice agnostic healthy eating. Take your cue from endurance athletes, Fitzgerald recommends. Most eat high-quality foods that fuel their performance without following a specific brand-name diet. Simply start where you are, then aim to eat more healthful foods like fruits and veggies, nuts and seeds, and whole grains, while cutting back on refined grains, sweets, and fried foods.