Beans are a healthy food, and they are also food non grata on the Paleo diet. Without necessarily agreeing with my Paleo friends, let me explain the seeming paradox.
The idea behind the Paleo diet is that many of today’s health problems are caused by foods and food products that are relatively new in human history. So the Paleo diet is about eating foods that our caveman ancestors ate, which included foods we could hunt, fish, gather or pluck – no grains or beans. But there’s another reason the Paleo crowd doesn’t like beans: lectins – or carbohydrate-binding proteins that plants developed to ward off insect predators. “Lectins can bind with almost any tissue in our bodies and wreak havoc,” writes Loren Cordain, PhD, in his book, The Paleo Diet (John Wiley & Sons, 2002).
Because of the lectin factor, other modern Paleo gurus like Mark Sisson, Robb Wolf and Esther Blum, ban beans and legumes as well. “Grains contain lectins which can damage the gut lining, which increases inflammation and is a newly discovered feature of not only autoimmune disease but also insulin resistance and liver pathology,” writes Wolf in The Paleo Solution (Victory Belt Publishing, 2010). (The lectins found in beans and other foods are also thought to contribute to the above conditions.) In her book, Cavewomen Don’t Get Fat (Gallery Books, 2013), Blum calls lectin “gluten’s sidekick” and notes that “lectin overload” can aggravate a number of health problems, including inflammation in the gut.
On the other hand, beans have some of the highest antioxidant firepower in the food kingdom. And they’re the highest-fiber food I know of, with 10 to 19 grams per serving. They also have a vanishingly low glycemic load. If you want to give the Paleo diet a try for 30 days, I see nothing wrong with trying it, and you may discover that you feel a lot better on it. But for most people, I think beans and legumes are terrific foods to consume.