I'm a nursing student who just finished a very rigorous Anatomy & Physiology course. I've struggled with my weight all of my life so I was very excited to learn how - physiologically speaking - our bodies use food.
Lypolysis - the breakdown of fat - cannot be accomplished in large quantities without carbohydrates in your blood stream. Long story short, the Krebs cycle is how our body uses fuel from food. A key component of the Krebs cycle (the system our bodies use to carbs, fats, & proteins, on a molecular level into energy) is oxaloacetic acid.
Here is a quote from my A&P book:
"When carbohydrates are deficient, oxaloacetic acid is converted to glucose (to fuel the brain). Without oxaloacetic acid, fat oxidation is incomplete . . . "
Bottom line, if you don't have sufficient carbohydrates in your system to fuel your brain and other organs that depend on glucose for fuel, your metabolism is unable to burn fat.
On the opposite end of the spectrum, some organs prefer their fuel to come from fat . . . the liver, cardiac muscle, and resting skeletal muscle.
Healthy weight loss means a healthy balance of all food groups - just like everybody who posted before me said.
