I do not believe that is true. I can eat greasy hamburgers minus the bun and feel completely fine. I thought the body would use fat and ketones to convert to energy and only convert a very small percentage of protein to glucose.

From the Harvard Medical School Family Health Guide:

"Don't be so refined. The bolus of blood sugar that accompanies a meal or snack of highly refined carbohydrates (white bread, white rice, French fries, sugar-laden soda, etc.) increases levels of inflammatory messengers called cytokines. Eating whole-grain bread, brown rice, and other whole grains smooths out the after-meal rise in blood sugar and insulin, and dampens cytokine production."

http://www.health.harvard.edu/fhg/updates/What-you-eat-can-f...