New York Times’ Gretchen Reynold just summarized a study which found that hyperglycemia blunts gains from exercise. Hyperglycemia happens for many reasons but primarily from insulin resistance. Saturated fat (and high fat diets) contribute to insulin resistance by impairing your cells’ ability to absorb glucose for energy. Simply stated, by eliminating saturated fat, processed food, sugar, and other concentrated sources of fat (oils), your cells will return to functioning the way they are supposed to.
The study pointed out that the diets comprised of high quality carbohydrates (i.e. fruit, whole grains, and starches) were the ones that led to higher gains. Sugar and fat = decreased gains from exercise. Fruit and whole grain = gains from exercise.
It’s worth noting that high fat diets also impair endothelial function and that low carbohydrate diets are linked to all cause mortality.
Stick to high levels of fruits, whole grains, vegetables, and starches. White potatoes are awesome. Do not eat fat.