Nutrition / Food

What Exactly Is a Lectin-Free Diet?

Here’s what to know about this trendy, but controversial diet.

The lectin-free diet is one of many popular diets trending recently. Naturally, this diet recommends avoiding lectins, a naturally-occurring group of carbohydrate-binding proteins found in almost all food. Typically, when we think of protein, especially protein that occurs in nature, we think healthy. So why would we want to remove these from our diets? According to the founder of the diet, California cardiologist Steven Gundry, M.D., a diet containing lectins leads to inflammation and weight gain. But, again, lectin is found in many good-for-you fruits, veggies, and whole grains. Here we discuss who, if anyone, should consider going on a lectin-free diet. To help us understand more about it, we turned to top registered dietitians to set the record straight.

What is lectin?

Lectin is a carbohydrate-binding protein found in a myriad of plant and animal foods. These include legumes, grains, milk, eggs, and vegetables, such as tomatoes, eggplant, peppers, and potatoes. Though naturally occurring, Miriam Amselem, holistic nutritionist, fitness trainer, and yoga instructor, explains that lectin binds to the cells on the gut wall. In large amounts, lectin can damage the gut wall. This prevents the gut from absorbing nutrients and causes irritation that can result in vomiting and diarrhea. However, she and many other nutrition experts agree that there are good nutrients in most of these healthy foods that outweigh the bad. This includes beans and grains that are sources of fiber and help regulate blood sugar.

What is the lectin-free diet?

The lectin-free diet calls for the removal of high-lectin foods from one’s diet. This includes grains, quinoa, legumes, nightshade vegetables, dairy, out-of-season fruit, and conventionally raised meat and poultry. The food that gets the green light includes leafy greens, nuts, seed, millet, pasture raised meats, and wild-caught fish. The goal of a lectin-free diet is to shed pounds and reduce inflammation. In fact, Dr. Gundry himself claims to have lost 70 pounds on the plan.

There is evidence to back up the benefits, including one 2006 study that linked consumption of a lectin-free diet to positive effects on those with cardiovascular disease and metabolic syndrome. Still, many experts are left unenthused.

The controversy over the lectin-free diet

According to Scott Schreiber, R.D., chiropractic physician and rehabilitation and clinical nutritionist, a lectin-free diet may actually cause more harm than good. You can find many vitamins and minerals in foods that contain lectin. “It is theorized that lectins are present in plants to discourage animals from eating them. Lectins can cause an upset stomach, which causes the animal to not eat that plant again,” he explains. “Translated to humans, it causes an inflammatory response. [This] can lead to other conditions, such as weight loss and IBS, and diseases including celiac disease, diabetes, and rheumatoid arthritis.” The bottom line, he points out, is that there’s not a lot of research that shows lectin is bad. “The diet is based on theory as opposed to fact.”

Christen Cupples Cooper, Ed.D., R.D.N., assistant professor and founding director of the Nutrition and Dietetics Program at the College of Health Professions at Pace University, agrees. She adds that there’s nothing in the scientific literature on humans that would indicate that lectin is a villain. In fact, she believes the lectin-free movement is just a classic example of a how these trends begin in the first place. A profit-driven handful of individuals promote a diet and supplements with no evidence to back them up. “As a registered dietitian with training on food chemistry, I’ve observed physicians (who receive no nutrition instruction in medical school) who try to popularize falsehoods,” she says. “Anytime you come across a diet that seems to cut out common-sense healthful foods, run the other way and save your money.”

Cook foods high in lectin.

The best thing to do, if you’re considering trying to reduce your lectin intake, is to cook any high-lectin foods you consume. This degrades most of the lectins in food, according to Becky Kerkenbush, M.S., R.D., Media Representative for the Wisconsin Academy of Nutrition and Dietetics. For example, boiling legumes in water eliminates almost all lectin activity. Other ways to degrade lectins include soaking or sprouting grains and seeds, as well as fermentation.

For those with severe gastrointestinal issues, reducing dietary lectin may actually be helpful to reduce diarrhea and enhance nutrient absorption, adds Erin Palinski-Wade, R.D., author of 2-Day Diabetes Diet. If you suffer from inflammation, she recommends consulting a nutritionist who specializes in digestive issues. They can oversee your diet in order to make sure you still get the nutrients necessary.

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