Lectins¹— sugar-binding plant proteins that attach to cell membranes — may be a hidden source of weight gain and ill health, even in an otherwise healthy diet. In fact, since lectins are present in most plant foods, if you’re eating a whole food diet yet find yourself still struggling with weight gain and/or stubborn health problems, lectins may well be a hidden culprit.

Many lectins are proinflammatory, immunotoxic, neurotoxic and cytotoxic. Certain lectins may also increase blood viscosity, interfere with gene expression and disrupt endocrine function.

The problem with recommending an altogether lectin-free diet is that this would eliminate most plant foods,² which should ideally make up the bulk of your diet. Moreover, in small amounts, some lectins can be quite beneficial,³ so 100 percent avoidance is likely neither possible nor ideal. They key then becomes finding a happy medium where the worst lectins are avoided, and the effect of others are tempered through proper preparation and cooking.

How Lectins Can Wreck Your Health

Before we get into strategies to reduce lectins in your diet, let’s review the reasons why. As explained in Dr. Steven Gundry’s⁴ book, “The Plant Paradox: The Hidden Dangers in ‘Healthy’ Foods That Cause Disease and Weight Gain,” some plant lectins can contribute to leaky gut by binding to receptor sites on your intestinal mucosal cells, thereby interfering with the absorption of nutrients across your intestinal wall.

As such, they act as “antinutrients,” and can have a detrimental effect on your gut microbiome by shifting the balance of your bacterial flora. Among the worst culprits are wheat germ agglutinin (WGA), found in wheat and other seeds in the grass family.⁵

Compared to WGA, gluten is a minor problem. According to Gundry, WGA is actually one of the most efficient ways to induce heart disease in experimental animals. Lectins in general are strongly associated with autoimmune disorders, so anyone struggling with a dysfunctional immune system may want to seriously consider experimenting with a low-lectin diet.

One way by which lectins causes harm is through molecular mimicry. By mimicking proteins in your thyroid gland or joint spaces, for example, lectins can cause your body to attack your thyroid and contribute to rheumatoid arthritis. Part of these disease processes is the penetration of the gut wall by lectins and their co-travelers, lipopolysaccharides (LPSs), also known as endotoxins, which tend to elicit very strong immune responses.  

Lectin-Rich Foods Best Avoided Entirely

While it may be near-impossible to avoid all lectins, seeing how they’re found in most plant foods, your first step would be to eliminate the worst offenders. If you have any kind of health problem in which lectins are a suspected contributor, it would be wise to eliminate the following entirely:⁶