Your genes have been in training for millions of years and each generation those ancestral nutrition lessons become more refined. The moment your very first great-great-great-great-parents ate their first meal, your body started learning what kinds of foods it needs to earn a grade of A++ in Feel Healthy School. Your DNA has been configured to function ideally when fed in a specific way.
Up until the time humans started moving around and intermingling with other tribes, it was easy to pick the healthiest foods… Nature was the grocery store, restaurant and Seven-Eleven!
Since humans switched from hunting & gathering to agriculture (only 10,000 years ago), food has changed dramatically. Our bodies have not had a chance to catch up to digesting processed grains, pasteurized dairy, refined fats and truckloadsfull of refined sugar.