By Marie Spano, M.S., R.D., Contributing Editor From the Atkins
diet to some forms of the Paleo diet, high-protein diets are
common for weight loss. Such diets restrict carbohydrate intake
so the body goes into ketosis, a metabolic state where it burns
its own fat for fuel. How effective are these and what are the
parameters? Ketosis is achieved by limiting carbohydrate intake,
resulting in decreased glucose availability, favoring fatty-acid
oxidation. Fat is converted into fatty acids and ketone bodies,
leading to increased blood ketones that serve as a fuel source
for cells that cannot use fatty acids for energy. As an
alternate fuel source, ketones attenuate muscle-tissue breakdown
for energy production (Cleveland Clinical Journal of Medicine,
2002; 69:849-962; Nutrition and Traumatic Brain Injury, National
Academies Press, 2011). A ketogenic diet is one that is low in
carbohydrate, though there is no universal standard for the
carbohydrate, protein or fat content. However, studies have
outlined varying am