The Plant Paradox claims that a lectin-free diet is the secret to weight loss, curing chronic disease, and more. But is it fact, or fiction? A nutritionist digs in to find out the truth.

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Though she’s a Grammy-award winning artist, Kelly Clarkson seems like the girl next door thanks to her down-to-earth approach on weight and body image. In fact, Clarkson shared last year that she’d made the decision to not work with those who pressured her about body weight. So Kelly’s noticeably slimmer physique at the CMT awards in early June naturally got people wondering about her diet.

Kelly says a thyroid condition triggered her to adopt a “clean eating” plan, which she based on Dr. Steve Gundry’s book The Plant Paradox. Since then, Gundry's book has been flying off the shelves, and the terms “plant paradox” and “lectin-free diet” are trending online. Clarkson is quick to say that “weight loss wasn’t the goal,” but her eating changes have resulted in a 37-pound weight loss—so what exactly is The Plant Paradox, and is it an approach we should all be following?

What Is The Plant Paradox About?

The Plant Paradox is based on Dr. Gundry’s theory that plants are smarter than we give them credit for and, like animals, they have defense mechanisms they use for survival. One of the primary forms of chemical and “biological warfare” that plants use on the human body to defend themselves is lectins—a group of proteins that can leak through intestinal walls into the bloodstream, where they disrupt neural and hormonal communication between cells and trigger confusion within the immune system to cause inflammation.

Dr. Gundry suggests that lectins—and these changes—are at the root of autoimmune conditions, weight gain, and most chronic health issues. The problem is, humans haven’t gotten smart enough to stop eating the foods that contain them.

What are Lectins—and Are They Bad for You?

Lectins are found in most foods—but particularly plant foods—and they are highest in legumes, whole grains, and some vegetables and fruits. Lectins are classified as “anti-nutrients” which means they are compounds known to reduce the body’s absorption or usage of a food’s nutrients.

From a biological perspective, lectins serve as a defense mechanism within plants to protect them from insects, fungi and pathogens, and some lectin-containing foods can cause illness if  eaten raw or undercooked. Dr. Gundry’s focus in The Plant Paradox is that plants use lectins as ammunition to attack the body and to deter humans from eating lectin-containing foods. He advises that humans should consume a lectin-free diet to heal the body and to restore health.

What Foods Contain Lectins?

Lectins are found in 30 percent of our food supply, so a “drastically-reduced lectin diet” is probably a better name than a “lectin-free diet.” Here are foods with little to no lectin recommended in The Plant Paradox, followed by foods high in lectin to avoid.

Foods with Little or No Lectin

  • Cruciferous vegetables, leafy greens, and other vegetables without seeds
  • Most fruits, in limited amounts
  • Some starchy vegetables (particularly those with resistant starch)
  • Most oils, tree nuts, and seeds
  • Wild-caught fish, grass-fed meat, and pasture-raised poultry
  • Goat and sheep milk and cheeses, milk, and cheese without A1 protein

Foods High in Lectins

  • All forms of grains, including whole, refined, and flours (wheat, quinoa, all forms of rice, oats, corn and corn products)
  • Beans, lentils, and peas
  • Soy foods like edamame and tofu
  • Fruits often referred to as vegetables such as cucumber, tomato, all squash, peppers, melons, and eggplant
  • Vegetables with seeds or beans, such as green beans and sugar snap peas
  • Peanuts, cashews, chia, sunflower, and pumpkin seeds
  • Cow’s milk, and most products made with cow’s milk (including yogurts, ice creams, and cheeses)

Lectins and Leaky Gut

Most lectins can’t be digested, but when eaten in appropriate amounts, this isn’t usually a problem in a healthy gut. Along with non-digestible fibers, many lectins will travel through the digestive tract to eventually become waste products. However, when gut microbes are reduced or unbalanced, gaps are created in the intestinal walls.

This allows nutrients to be absorbed through intestinal walls as in a healthy gut, but these gaps also allow undigested and foreign compounds to “leak” into the body—sometimes referred to as leaky gut. This leaking can trigger an inflammatory response within the body when certain lectins are consumed in excessive amounts or when an individual has a sensitivity to particular lectins.

 

Debunking The Plant Paradox: What’s Fact, What’s Fiction?

There’s nothing I love more than new research changing the way we think about nutrition and health—BUT it’s got to be from a professional source and have substantial, credible references to back it up. So, I was intrigued to learn more about Dr. Gundry’s theories because of his medical background and the numerous references given throughout the book.

However, what I found when reviewing many of those citations was that he repeatedly takes the liberty to embellish scientific study results or to spin results slightly toward his viewpoint. In addition, he cites websites such as ProteinPower, Dr. Axe, and The Beef Site as credible sources for health information—sources that wouldn’t even fly on a high school research paper.

There are some bits of truth within his book though, and Dr. Gundry’s lectin-free diet recommendations appear to be the answer to weight and health issues for many. So before jumping on The Plant Paradox bandwagon, let’s take several of Dr. Gundry’s key points and separate what’s backed by scientific research from what’s a a half-truth or exaggeration.

1. Lectins cause inflammation.

This is partly true. There are numerous studies suggesting that lectins can trigger an immune response in certain individuals with a lectin sensitivity, food allergy, or autoimmune condition. These people would likely benefit from eliminating certain lectin-containing foods. There are at least 119 types of identified lectins, though, so even sensitive individuals may not have to eliminate all lectin-containing foods.

In terms of lectin being inflammatory for the general population, there are few, if any, humans studies to support this—only ones done in a lab or on animals. Additionally, there is overwhelming research to suggest that key lectin-containing foods have an anti-inflammatory effect. In fact, increasing overall consumption of fruits and vegetables is actually associated with decreasing inflammatory markers in the body and reducing risk for many inflammation-related conditions. Intake of lower-glycemic, whole-grains is also associated with reduced inflammatory markers.  

2. Lectins cause weight gain.

Dr. Gundry states that lectins “stimulate weight gain,” but this has not been proven to be true. In fact, there’s substantial research to suggest the opposite. Higher whole-grain and legume intakes is associated with having a lower BMI, and increasing consumption of beans, lentils, and peas appears to support weight loss. Increased fruit and vegetable intake has not been found to cause weight gain and is associated with weight loss maintenance.

3. Lectins are "toxic" to the body.  

This is true; large amounts of certain raw lectins can cause nausea and vomiting. Raw red kidney beans are an example that can trigger illness due to toxicity from a certain lectin. But who eats kidney beans raw? Proper cooking reduces those lectins in red kidney beans to safe levels, and cooking drastically decreases lectin levels in all food.

Furthermore, lectins may actually have therapeutic uses in the body. One of the most promising is in treating cancer since certain lectins have demonstrated potential to kill cancers cells and halt cancer growth.

4. Lectins are the cause of most health issues.

This is not true. The current consensus is that the powerful positive benefits associated with antioxidant compounds, fiber, and other nutrients in lectin-containing foods like produce, legumes, and whole grains greatly outweighs any potential negatives. In fact, increasing overall consumption of fruits and vegetables is associated with a reduced risk of heart disease, stroke, high blood pressure, some cancers, and type 2 diabetes. Higher whole-grain consumption is associated with a lower risk of cancer and heart disease, and higher legume intake with reduced cholesterol, improved blood pressure, and better glucose response.

The Bottom Line: There’s nothing that I love more than challenging existing science knowledge, but The Plant Paradox hasn’t presented me with compelling credible research to advocate a lectin-free diet for the average person. I can’t agree that lectins are at the root of health issues, and I definitely can’t agree that health will improve by avoiding lectin-containing foods like legumes, whole grains and many vegetables and fruits