Barley may be lower on the glycemic index than wheat, but it’s still very high in carbohydrates, and it’s a grain that contains gluten.
Grains as Processed Food
One of the first steps to living a Paleo lifestyle is to rid all processed food from your diet, and you’d be hard pressed to come across any grains in the grocery store that have not been processed. Making them edible requires a fair amount of human intervention, and the payoff isn’t worth it because they aren’t even that nutritious. They have small amounts of vitamins and minerals, but you can get a much higher serving of these nutrients from meat, eggs, fruits and vegetables without feeling hungry two hours later.
Why We Should Avoid Gluten
To make matters worse, gluten is a serious anti-nutrient. It allows toxins and undigested foods to pass through the lining of the intestine and into the bloodstream. The body responds by rushing white blood cells to the area to fight off the foreign substances. This immune response involves inflammation, which is why people who consume gluten on a regular basis tend to have chronic inflammation. Most of us living a Paleo lifestyle try to avoid chronic inflammation because it is a dangerous precursor to all sorts of chronic maladies, including arthritis and allergies.
For more reasons to avoid grains, check out this post by Mark Sisson.