Lectins are a type of protein present in many foods. Some people recommend lectin-free diets. However, there is insufficient evidence to support their benefit or safety.

Lectins are a type of protein present in many plant-based foods.

Some people believe that excluding lectins can help people lose weight and improve their general health. However, there is insufficient evidence to support a lectin-free diet.

Restrictive diets can be dangerous and lead to serious complications. A person should not engage in restrictive diet practices without medical oversight.

Lectins occur in many different food sources in many different forms. Advocates of lectin-free diets typically focus on avoiding the lectins present in beans, legumes, and other vegetables.

However, these foods can be important parts of a balanced diet, and there is no high-quality research supporting their removal from a person’s diet.

In this article, we look at the research into lectins and the lectin-free diet.

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Dr. Steven Gundry first coined the term “lectin-free diet.” He is a former heart surgeon who now promotes alternative diets and supplements.

Advocates claim that excluding foods high in lectins from the diet can have numerous health benefits, such as weight loss and prevention of chronic conditions.

Despite its popularity in some areas, there is no comprehensive evidence that a lectin-free diet has any health benefits.

Lectins are a type of protein that may promote cell development and support cell communication. They also play a role in the human immune response.

A 2015 review estimates that around 30% of the food people consume in the United States contains lectins.

There are several types of lectins in both animals and plants. Foods high in lectins include beans, legumes, and bell peppers.

Lectins are typically harmless when eaten in moderation. Thorough cooking of foods high in lectins can mitigate many of their potentially harmful effects.


If a person has underlying health conditions that impact their digestive enzymes, consuming excess lectins may lead to nutrient deficiencies and digestive problems. This is because the body cannot break down lectins, so they may bind to the cells lining the gastrointestinal tract instead.

However, lectins often attach to carbohydrates and leave the body before they can have a negative impact on a person’s health.

People should only exclude food groups from their diet following a doctor’s recommendation.


Most lectins are harmless to human health, while others, such as ricin, can be fatal in small amounts.

The type of lectin present in red kidney beans is called phytohemagglutinin. It is responsible for red kidney bean poisoning, which comes from eating raw or undercooked kidney beans.

According to the Food and Drug Administration (FDA), consuming just 4 raw kidney beans could cause symptoms such as severe nausea, vomiting, and diarrhea.

Some people categorize lectins as antinutrients, as they block the absorption of some nutrients.

However, thoroughly cooking high lectin beans and legumes can make them harmless to humans.

Weight gain

Advocates of a lectin-free diet often claim that lectins lead to weight gain. However, reviews into the effects of pulse consumption on body weight show that diets rich in beans and legumes are actually associated with lower body weight.

The nutrients that accompany lectins in plant-based foods are also essential. Removing them from the diet may have damaging consequences.

The lectin-free diet involves excluding all lectins from a person’s diet. The originator of the term claims that lectins interfere with the body’s natural digestive systems and can cause:

  • nausea
  • bloating
  • weight gain
  • vomiting
  • issues with the immune system

People who advocate a lectin-free diet often claim that it can improve overall health and help reduce body weight.

However, no evidence supports the exclusion of lectins from the diet. A person should only make major changes to their diet following recommendations from their doctor.

For most people, there are no health benefits of a lectin-free diet. Beans, legumes, and other lectin-rich foods are good sources of nutrients, proteins, and fibers that can play an important role in a balanced diet.

A person should only exclude certain foods from their diet on the advice of their doctor.

The lectin-free diet is a restrictive plan, which may make it difficult for some people to follow it long term. The plan also limits or eliminates many nutritious foods, such as whole grains, beans, and certain vegetables.

A 2016 review of 45 studies showed that consuming whole grains has associations with a reduced risk of overall mortality and several conditions, including heart disease, diabetes, and various cancers.

Fruits and vegetables also have many health benefits. Eating fruits and vegetables may lower the risk of several conditions, including heart and lung diseases. These foods may also impact cancer risk and help prevent weight gain.

A lectin-free diet may be difficult for vegetarians or vegans to follow, as legumes, nuts, seeds, and whole grains provide plant-based protein.

Learn more about the difference between vegetarian and vegan diets here.

Legumes, whole grains, and fruit and vegetable peels also provide dietary fiber. A lectin-free diet could result in constipation if dietary fiber intake decreases.

The following foods have low lectin content:

The following foods are high in lectin:

  • squash
  • legumes, including beans, peas, lentils, and peanuts
  • nightshade vegetables, such as eggplant, peppers, potatoes, and tomatoes
  • fruit, although the diet allows moderate amounts of in-season fruit
  • grains

There are many kinds of lectins, the majority of which are harmless to humans and provide health benefits.

Although lectins may cause problems for people with an intolerance or people who eat them in excess, there is strong research to support the benefits of eating plant-based foods.

Advocates of a lectin-free diet claim that it can aid weight loss and improve overall health and well-being. However, there is insufficient evidence to back up any of these claims or the safety of a lectin-free diet.

Restrictive diets can often lead to malnourishment or disordered eating. A person should always talk with their doctor before drastically changing their eating habits.