To a die-hard follower of one of these diets, what they put on their plate is as personal as their political party–and just as controversial. These four food philosophies have small, dedicated, and sometimes fanatical followings. So which are legit? We asked the experts to separate the facts from the fads.
Vegans nix all animal products, including meat, dairy, gelatin, and eggs. How passionate are herbivores? Lierre Keith, a former vegan and author of a book criticizing vegetarianism, got chili pepper pies in the face at an appearance in 2010.
Is it legit? Research in the American Journal of Clinical Nutrition shows that vegans are usually thinner and enjoy a lower risk of heart disease, diabetes, and cancer. Why? They generally eat a more wholesome diet, including more fiber, fruits, vegetables, and legumes and avoid processed meats. But still, meat can be part of a healthy diet. Case in point: In another study in AJCN in 2012, researchers put people on a healthy diet that included up to 5.4 ounces of lean beef a day in lieu of chicken or fish. The results: Their cholesterol scores dropped about 10 percent. (Want to try a no-diet, no-workout plan that’s better than running 5 miles a day? Check out The Lean Belly Prescription.)
Maybe you’re Drew Brees and have an allergy to gluten–or you suffer from celiac disease, an autoimmune condition where the lining of the intestine is damaged and doesn’t properly absorb nutrients. Or, maybe you have non-celiac gluten sensitivity. Not surprisingly, if that’s you, you should avoid gluten (a protein found in wheat, rye, and barley). But thanks to celebs like Russell Crowe, a gluten-free diet is touted as a sure-fire way to slim down.
Is it legit? Yes, if you have a real problem digesting gluten diagnosed by your doc. (Symptoms can range from gastrointestinal discomfort and bloating to headaches and fatigue.) However, according to a 2012 study in Archives of Internal Medicine, many people with food sensitivities restrict gluten (and other foods) without a proper diagnosis. Then they attribute any improvement in symptoms to going gluten-free, when really it could be a number of different factors. The bottom line: Sure, going gluten-free can help you lose weight if you cut back on processed carbs and eat more whole foods. But “merely switching to gluten-free processed products or desserts, which many people do, won’t help you trim down because these contain just as many calories as the regular versions,” says Chicago-area registered dietitian Breea Johnson. (There’s even more about gluten, the food industry, and your belly that you need to know. See Why Gluten Is Making You Fat.)
Channel your caveman hunter-gatherer ancestors and subsist on lean meat, fish, vegetables, and fruit; skip sugar, grains, dairy, beans, and legumes. The basis? We should follow a diet our bodies evolved to eat, devotees claim.
Is it legit? A small study by researchers at the University of California, San Francisco, found that, compared to when people consumed their “normal” diet, switching to a paleo diet for 10 days lowered their blood pressure and cholesterol and improved insulin sensitivity. An earlier study on 14 people found that following a paleo diet for three weeks led to about a five-pound weight loss. Though these are small studies on the specific paleo diet, the broader tenets–eat real foods, avoid processed junk–are sound advice for anyone. Foods high in refined sugar and processed carbs–like cookies, crackers, and chips–are typically calorie-dense, so cutting these out of your diet will probably help you lose weight.
Raw foodists claim that foods (beans, fruits, vegetables, dairy) are most nutritious when eaten raw. You’ll need one thing for sure: lots of free time to peel, chop, and blend all that produce.
Is it legit? A 2005 study in The Journal of Nutrition analyzed health markers in 200 people following a raw food diet for an average of 3.5 years. Overall, a raw diet was associated with low cholesterol and triglycerides but–the bad news–nearly 40 percent of participants were vitamin B-12 deficient and nearly half had low “good” HDL cholesterol. Yes, cooking destroys some nutrients (like vitamin C) but it also enhances the concentration of others. Take tomatoes, for example: more lycopene is released when they’re cooked versus raw. It’s a trade-off, but you’ll get plenty of vitamins and minerals whether consuming that carrot, tomato, or broccoli raw or cooked, says Johnson.