One of my least favorite things about fad diets is the long list of forbidden foods. Eliminating a lot of foods is psychologically hard, often unnecessary, and ultimately causes people to rebound. But what especially irks me is when those lists have the nerve to include nutritious foods, ones that most people should actually be eating MORE of, instead of excluding them.
One of the most recent examples: the lectin-free diet, which got a lot of attention thanks to a diet book written by a heart surgeon--and to singer Kelly Clarkson, who credited the diet with helping her feel better and drop weight. The lectin-free diet is centered around the idea that we should avoid certain plant foods that are rich in proteins called lectins. Lectins are sometimes referred to as “anti-nutrients” because they bind to carbohydrates as well as some minerals like calcium and zinc. Proponents of this diet claim that lectins trigger inflammation, weight gain, and even autoimmune disorders like lupus.
But there are a few problems with the case against lectins. First, lectins are found in a lot of foods that are truly good for you, like beans, lentils, peanuts, potatoes, peppers, eggplant, tomatoes, zucchini, whole grains, oats, corn, and even fruit. There’s a whole body of research showing that diets rich in foods like whole grains, beans, and lentils are good for health, reducing the risk of conditions like heart disease and diabetes and linked to a healthy body weight too.
Second, lectin levels are higher in raw foods. Cooking reduces and deactivates lectins, rendering the lectins in dry beans, for instance, a non-issue. And lastly, the research on the “dangers” of lectins is quite thin, with some studies focusing on populations with very limited diets. In fact, there are studies showing possible health benefits of lectins, including possible antioxidant and cancer-fighting properties.
If you have a health condition such as an auto-immune disorder, it’s understandable that you would want to look for diet-related changes that might bring relief. Reducing or eliminating foods for a certain period of time to see if you feel better is a reasonable approach. In fact, Clarkson said her goal in trying the lectin-free diet was to help treat an autoimmune disorder.
For the rest of us, there’s no reason to avoid this long list of healthy foods. I’ve been a dietitian for more than a decade, and I feel confident saying that beans and squash are not a problem. (Nutrition misinformation, on the other hand, is.)