The statistics tell a scary story. More than one-third of U.S. adults—close to 80 million people, according to the Centers for Disease Control and Prevention—are obese, and as Americans’ waistlines continue to grow so do rates for chronic health conditions such as Type 2 diabetes and cardiovascular disease.
But does the path to weight loss and better health lie in eating like our hunter-gatherer ancestors, eschewing grains, dairy products and the other foods of the modern agricultural era in favor of protein, nonstarchy vegetables and healthy fats such as coconut oil?
That’s what advocates of a paleo diet say. Government health experts in Washington, though, seem to disagree. The latest dietary guidelines from the U.S. Agriculture Department encourage Americans to consume whole grains and dairy products on a daily basis, and to avoid foods high in fat.
Arguing in favor of a paleo diet is Kellyann Petrucci, a naturopathic physician, certified nutritional consultant and clinical director of Birmingham Wellness Center in Birmingham, Mich. Making the case against it is Marion Nestle, a professor of nutrition, food studies and public health at New York University and author of “What to Eat.”
YES: It Helps Control Weight and Lowers Risk of Cancers
By Kellyann Petrucci
I prescribe a paleo diet for my patients because I’ve found that it is the best diet to foster weight loss and good health.
In contrast to high-carbohydrate diets that have led to skyrocketing rates of diabetes, obesity and inflammatory diseases, a paleo diet can reduce inflammation, reverse diabetes symptoms, lower blood pressure and cut cancer risk by providing a template of foods that are as close to nature as we can get today. Science backs me up.
A study published last October in Lipids in Health and Disease found a paleo diet to be more effective in reversing metabolic syndrome (the first step toward diabetes) and cardiovascular risks in patients with extra belly fat or other risk factors for diabetes than a diet based on standard guidelines. What’s more, the paleo group lost more weight even when the researchers tried to keep their weight stable by adding extra calories.
A study published in Cardiovascular Diabetology in 2009, meanwhile, compared a paleo diet and a standard low-fat diabetic diet on people with Type 2 diabetes. The paleo group ended up with lower HbA1c levels (a long-term measure of blood sugar), lower triglyceride and blood-pressure levels, and higher levels of “good” cholesterol. They also lost more weight and belly fat.
Many doctors believe a Mediterranean diet—emphasizing whole grains, low-fat dairy foods, vegetables, fruits, fish and olive oil—is the best. However, a 2007 study in Diabetologia comparing it to paleo found that in patients with ischemic heart disease, the paleo diet led to better glucose tolerance and a larger drop in abdominal fat.
Because it is low in carbohydrates, a paleo diet may cut your risk of cancer. A 2014 study in Cell suggests a low-carb diet can reduce the risk of colon cancer, and a 2011 study in Cancer Research indicates it may lower the risk of breast cancer. A diet high in carbohydrates, in contrast, increases the risk of colon cancer.
Critics of the paleo diet like to point out that it isn’t low in saturated fats. However, a recent meta-analysis of more than 70 studies found no evidence that saturated fat is bad for your heart or that other kinds of fats are more beneficial. Moreover, the fats in a paleo diet come from natural sources such as coconut oil—not from heavily processed seed oils.
Some nutritionists charge that by eliminating certain food groups such as dairy, a paleo diet can lead to nutrient deficiencies. That criticism is flawed, too. Paleo foods such as salmon, sardines, kale, broccoli and figs are rich in calcium, and you can get the same fiber and nutrients from vegetables, healthy oils, seafood, eggs, meat and fruits as you get from beans, grains and soy. And you’ll get them without overloading your body with gluten (to which many people react badly), insulin-spiking carbs and phytic acid, which impairs your uptake of crucial minerals like calcium and iron.
The great thing about the paleo diet is that it doesn’t require you to give up cultural traditions or foods you love; it simply asks you to adapt them in ways that make you healthier. My family adores my Italian grandmother’s marinara sauce tossed with spaghetti squash strands or zucchini ribbons.
In short, I prescribe a paleo diet for my patients because science shows it is healthier, and that’s why I believe you should follow it, too.
Dr. Petrucci is a naturopathic physician, certified nutritional consultant, and clinical director of Birmingham Wellness Center in Birmingham, Mich. Email her at firstname.lastname@example.org.
NO: You Lose Too Much Pleasure for Dubious Benefits
By Marion Nestle
Nutritionist that I am, the first questions I have about any diet are: What is it? Is the rationale behind it logical? And does it promote health?
A paleo diet is based on the premise that our genes govern what’s best for us to eat. We evolved to eat whatever could be hunted or gathered. This makes it OK to eat leaves, shoots, roots, seeds, eggs, animals, birds and fish, but not OK to eat grains, legumes, dairy or processed foods.
Why do paleo proponents think the ills of modern society stem from a mismatch between our genetics and today’s typical diets? The cave men, some argue, didn’t suffer from diseases such as obesity, heart disease and diabetes.
The problem with that theory is that we really don’t know what our Paleolithic ancestors ate. As I often argue, determining what people eat is the single most intellectually challenging question in nutrition science. It is extraordinarily difficult to get an accurate idea of what people ate yesterday, let alone 10,000 to a million or more years ago.
In reality, scientists are nowhere near being able to match genes to specific kinds of diets. The reason cave men didn’t have chronic diseases like diabetes is more likely because they didn’t live long enough and lacked antibiotics, rather than because they didn’t eat carbohydrates.
Variety is key
What we know for sure is that the fundamental tenets of nutrition are variety, balance and moderation. The fewer kinds of foods consumed, the greater the chance of nutrient deficiencies. So while it is certainly possible to eat healthfully on a paleo diet, restricting whole groups of relatively unprocessed foods can make this more challenging. It also can take some of the joy out of eating by forcing people to give up foods that they love or that are part of their cultural heritage.
While there is no doubt that highly processed “junk” foods are unhealthy and should be kept to a minimum, grains and legumes are hardly the enemy. Diets that vary enormously—from the traditional high carbohydrate, rice-based cuisines of Asia to those of the Mediterranean rich in grains and olive oil—have been shown to promote health and longevity.
Yes, grains contain glutens, and bread and pasta are caloric, but such foods are also delicious and part of traditional diets in nearly every culture. Yes, legumes contain unpleasant phytochemicals, but these are mostly destroyed by cooking, and beans and peas are excellent sources of vegetable protein. If you eat foods from animal sources, why restrict dairy? Cheese and yogurt are lovely foods, and I, for one, cannot imagine life without an occasional serving of ice cream.
Eating less works
Any restrictive diet helps to reduce calorie intake, so it isn’t surprising that there are studies linking paleo to weight loss, lower blood sugar and a reduced risk of cancers for which obesity is a risk factor. Eating less works every time.
So does eating a largely plant-based diet. Research suggests that we can reduce risks for today’s diseases of affluence by eating more foods from plant sources and balancing calorie intake with expenditure. To the extent the paleo diet achieves these goals, it is a reasonable choice.
But food is so much more than bundles of nutrients. What we eat also nourishes us psychologically and culturally. So while a paleo diet isn’t necessarily bad, why bother? I’d be sad to miss all those delicious forbidden foods.
Dr. Nestle is a professor of nutrition, food studies and public health at New York University. Email her at email@example.com.
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