THE BASICS: Free radicals are created by natural processes in your body and as a reaction to external stressors like pollutants, alcohol, unhealthy trans fats and stress. Your body is used to dealing with them and they are even useful when kept at manageable levels. They become harmful when they get out of control. How do you keep free radicals in check? It’s really pretty easy. Eat a diet that is mostly fresh (& organic) vegetables, fruits and free range lean meat and limit processed foods and read nutrition labels.