(CRISTINA BYVIK/FOR THE…)
With swimwear season in full swing, many would-be beach bodies are hitting the gym — and the books. Diet books are on many bestseller lists, and that’s not surprising, says physician David Katz, director of the Yale University Prevention Research Center.
“We know what to feed our aquarium fish, but we don’t know how to feed ourselves,” Katz says, so we can’t resist the lure of an easy answer. But do these top diets deliver what they promise? Here’s what the experts had to say about some of the most popular diets and the books behind them.
‘Wheat Belly’: Cut the gluten
In the bestselling book “Wheat Belly,” cardiologist William Davis writes that modern, genetically modified strains of wheat are the cause of most Americans’ health problems, including expanding waistlines, arthritis and hypertension. He blames gluten, a protein found in wheat and related grains, such as barley and rye, that can cause an autoimmune response in people with celiac disease.
According to Davis, all people fare poorly on gluten, whether they have celiac disease or not, and swapping gluten-loaded breads and pastas for vegetables, meats and other wheat-free foods will lead to weight loss and better overall health.
The problem with this premise is that there’s little evidence to support it, says Lawrence Cheskin, director of the Johns Hopkins Weight Management Center and associate professor of health, behavior and society at the Johns Hopkins Bloomberg School of Public Health.
“It’s really a small group of people who have a pathological response to gluten,” Cheskin says. “And for them it’s absolutely essential to eat a gluten-free diet. Everyone else may be limiting their choices unnecessarily.”
Limiting those choices may not always be a bad thing, however, Katz says. “If you cut out crackers and cookies and cakes, you’re taking in a lot fewer calories, and you may lose weight,” he says, “but it has nothing to do with the gluten.”
Katz urges readers to approach Davis’s popular anti-wheat polemic with caution, and not trade one set of unhealthful habits for another. “It’s entirely possible to eat gluten-free junk food, too,” he says. “Now that it’s caught on, there’s a proliferation of highly processed gluten-free foods. You can definitely cut gluten and still get fatter and sicker.”
‘The Paleo Solution’: Stone-age cuisine
The paleo diet also goes against the grain — literally — in its recommendations, which emphasize the foods that humans’ Paleolithic ancestors ate: meats, preferably wild or grass-fed, vegetables, fruits, nuts and seeds. Robb Wolf, a former biochemist, didn’t start the paleo trend, but he presents its scientific case in “The Paleo Solution.” In it, he details the anthropological and biological evidence behind paleo claims that humans haven’t evolved to digest grains and other foods that became widespread after the birth of agriculture and that people can find optimal fitness and health on pre-agricultural fare instead.
Wolf’s argument — along with the paleo diet itself — has its merits, Katz says.
“The paleo diet is a contender for the best diet out there, if you do it right,” he says. That means getting plenty of fiber-rich vegetables and eating game such as wild-caught fish and venison. “But many people use paleo as an excuse to eat hamburgers or hot dogs, and we know that there were enormous differences between the meat our ancestors ate and the meat we have now.”
Doing paleo the right way is also difficult because of its very structure, says Marion Nestle, a professor of nutrition at New York University.
“Any diet that excludes one or more entire categories of foods is difficult for many people to follow,” Nestle says. “For some people, it’s easier to exclude whole categories — wheat, meat, dairy, carbohydrates, et cetera — than to just eat less and eat better. But the more food categories excluded, the more people are likely to give up on the diet.”
‘Clean’: Drinks that detoxify
Exclusion is at the heart of cleansing diets, including the “Clean Program” popularized by celebrities such as Gwyneth Paltrow. The Clean Program, a 21-day detox based on the book “Clean” by physician Alejandro Junger, requires giving up caffeine, sugar, wheat, soy, red meat, raw fish, alcohol and an assortment of other foods, and replacing breakfast and dinner with homemade smoothies, juices or soups. Junger claims that exposure to toxins in everyday life, through poor dietary choices (think junk food) takes a toll on the body and that his liquid-centric three-week regimen helps the body heal itself.