In a world where almost any food is capable of presenting a health concern, there is a new movement that suggests something that seems almost impossible to be true: are compounds found in fruits and vegetables making you sick and fat?

There's a book called The Plant Paradox, which suggests that lectins are the cause of many health issues. For most people, "lectins" is a foreign word, but they are not found in foreign foods. Lectins are proteins found in around 30 percent of the foods we eat, including many fruits and vegetables, whole grains, nuts, and beans.

The book suggests that lectins are toxic and, even in low doses, lectins can cause long-term health effects like chronic disease and inflammation.

Before you panic, there's no need to stop eating many of the foods you think are healthy. Some people will need to avoid lectins, but the problem is not anywhere near as dangerous as it seems.

What are Lectins?

Lectins are proteins found in around 30 percent of the foods you eat, such as legumes, peanuts, lentils, tomatoes, potatoes, eggplant, fruits, and wheat. While there are some toxins in these foods (specifically in foods like raw kidney beans), they are not dangerous.

That's because the cooking process denatures the lectins, meaning they are harmless.

This is why you can get severely ill from eating raw kidney beans, but not from canned kidney beans.

Other common lectin-containing foods are nightshade vegetables, pulses, and grains, and seeds, like quinoa and chia. While it's fair to say that some people don't tolerate lectin-containing foods as well as others, there's no need to fear that eating these foods will make you pack on pounds.

After all, there is no evidence to suggest that lectins are the cause of chronic disease or obesity.

Is There Any Real Danger?

The healthiest, longest-living people on earth live in areas known as "Blue Zones." These populations have been studied excessively, and one of the most common traits are a plant-rich diet that includes lectin-containing foods.

This is the first of many challenges to the assumptions made by The Plant Paradox about the dangers of lectins.

If you keep going down the rabbit hole, the claims look harder and harder to believe. Chickpeas have been cultivated since at least 3200 BC, and lentils enjoyed for at least 8000 years. Aztecs used tomatoes in their cooking.

We’ve evolved to not get sick from lectins by learning to cook food to denature any dangers. In fact, nations that eat fewer lectin-containing foods (like the United States) have a higher incidence of chronic disease than countries such as Greece and Italy, where they commonly eat legumes, grains, and nightshades.

As with any choice, when you can remove fear, you can make better decisions and determine what is best for you.

Who Should Avoid Lectins?

Some people can benefit from avoiding lectins, just as there are people with gluten allergies who should avoid gluten.

If you have dysfunctional enzymes, then lectins may cause autoimmune issues for you because they might compromise your intestinal barrier. It’s entirely probable that autoimmune diseases such as rheumatoid arthritis are related in part to dietary factors, and lectins could be one of them.

Or, if you have an autoimmune disease or a digestive disease such as IBD, you may feel better by eliminating lectins from your diet. Even if removing them helps with your symptoms, you probably don’t have to eliminate all lectin-containing foods. An elimination diet can reveal which ones cause you issues and which ones don’t.

How To Assess Your Diet

The fear of lectins is not an isolated incident. Many diets try to strike fear around a specific food rather than helping you understand what is the best fit for you.

As a dietitian, I want to make it as easy as possible for you to navigate the confusing world of dieting.

If you try this diet (or any diet for that matter) and find that your health issues resolve, then that's a good thing. But, there's a big difference between finding something that works for you and assuming that certain foods (especially those with many documented health benefits) are toxic.

A lectin-free diet forbids many foods that are perfectly safe and nutritious. Instead, a better place to start is by looking to limit (but not necessarily fully remove) ingredients that are in every junk food. When that happens, you’re sure to lose weight. 

But remember, good nutrition sometimes includes cake. And pizza. And enjoying meals with friends and family without being anxious about what you’re eating.

The truth is that most people don't eat enough plants, so make sure that before you go cold turkey and avoid all lectins, that you ensure you are not removing all the food from your diet that is the foundation of healthy habits.