High fibre foods such as vegetables and salads must be avoided before a workout as they would take too long to digest. (bodybuilding-wizard.com)
The main reason counting calories doesn't work is because it doesn't take into account high fibre foods. (conscious-foodie.com)
But humans have been consuming high fibre foods and herbs for a very long time, and there is no rational reason why we should not be able to now. (foodasmedicine.ca)