The first step to living a Paleo lifestyle is to rid your diet of all processed foods. Skip the fast food restaurants (most restaurants for that matter), make your own food, and shop only the edges of the grocery store, and you’re way ahead of the rest of the pack.
A Whole Foods Diet
Tofu definitely qualifies as a processed food, which means we can’t include it on the Paleo menu. It’s made of soy, which by now is almost always GMO. Then it’s processed beyond recognition and offered up as a plant-based source of protein.
Paleo and Phytates
Aside from the fact that soy is almost always genetically modified, it’s a legume that comes packed with anti-nutrients, including phytic acid that is known to interfere with mineral receptors in the body, creating nutrient deficiencies.
Mark Sisson has a comprehensive list of the pros and cons of soy.