Nutrition Performance - Current Contoversy
Post-exercise, High-glycemic Carb Ingestion: Friend or Foe?
Pull Quote:
post-exercise high-glycemic carb ingestion are worrying about a non-issue.
It seems to me that the guys who are afraid about fat gain as a result of"The importance of nutrition following training-induced homeostatic disruption can be
traced to our most ancient of writings. Esau, the firstborn of Isaac, in what is estimated to be
1800 B.C. appears to have had incredible genetics. His training sessions, however, were not
found in the gym, but rather in the field, as he hunted the most ferocious of beasts. So vital was
the post-workout meal to the father of the Edomites, that he sold his birthright to his brother
Jacob for it!" –Jacob Wilson, HYPERplasia The Magazine
Glycemic Index and Sports Nutrition
The glycemic index is a ranking of carbs according to the extent to which they raise
blood sugar levels after eating. Foods with a high-glycemic index are those which are rapidly
digested and absorbed and result in marked fluctuations in blood sugar levels. In general,
sports nutritionists recommend that one ingest low-glycemic carbs before exercise and highglycemic
carbs immediately after exercise. Less postprandial hyperglycemia and
hyperinsulinemia have been observed after the consumption of low-glycemic foods when
compared with high-glycemic foods.
stable blood sugar levels and maintain free fatty acids at higher levels during exercise, which in
turn promote fatty acid burning. On the other hand, a high-glycemic carbohydrate-rich meal may
be beneficial for the glycogen storage and muscle protein anabolism after exercise by
promoting greater glucose and insulin responses.
concern for the physique athletes, high-glycemic carb ingestion immediately after resistance
exercise can decrease muscle protein breakdown and urinary urea excretion, resulting in a
more positive body protein balance.
1 Such metabolic and hormonal responses promote more1 While rapid glycogen resynthesis is seldom a2Post-exercise, High-glycemic Carb Ingestion Promotes Fat Gain? Hardly
2max.3 Indirect calorimetry indicated that glucose ingestion in post-exercise4 Finally, Dr. Bird and co-workers observed that post-exercise ingestion of high-glycemic5 In summary, it seems to me6 While amino acid ingestion alone significantly increases muscle protein anabolism7 consumption of both amino acids and carbs result in much greater8 suggesting an interactive effect between insulin, aminoSome have speculated that post-exercise ingestion of high-glycemic carbs may inhibit
fat loss. However, I feel this is hardly a concern for the serious athlete when carbs are ingested
immediately after rigorous exercise, when the muscle cells are highly receptive to insulin and
"screaming" for new fuel. It must be realized that the physiological state of a sedentary
individual in comparison with a well-trained athlete following exercise are polar opposites. The
so-called AMP-activated protein kinase acts as a "metabolic switch" in multiple tissues after
exercise; the net effect of its activation is to increase fatty acid burning and diminish storage fat
synthesis.
To investigate the hormonal and metabolic adaptations occurring when high-glycemic
carbs are ingested after exercise, Dr. Krzentowski and co-workers compared the fate of a 100-
gram oral glucose load in healthy volunteers after an overnight fast at rest, either without
previous exercise, or after a three-hour exercise performed on a treadmill at about 50 percent of
the individual VO
recovery was associated with decreased carbohydrate burning and increased fat burning when
compared to control conditions.
More recently, Dr. Folch and colleagues reported that de novo lipogenesis (the
metabolic route by which mammals convert excessive dietary carbs into fat) is totally
suppressed following exercise, even when a very large carb load is ingested, and that fat
burning remained high in subjects who had exercised following both the small and large carb
meal.
carbohydrates doesn’t inhibit resistance training-induced fat loss.
that the guys who are afraid of fat gain as a result of post-exercise, high-glycemic carb ingestion
are worrying about a non-issue.
Don`t Forget Aminos, Dude!
Obviously, you also have to take in some amino acids immediately after exercise, as
protein balance over the muscle remains negative after resistance exercise when only carbs are
ingested.
after resistance exercise,
effects on muscle protein anabolism,
acids and resistance exercise.
Interestingly, a recent placebo-controlled study reported that post-exercise protein-carb
supplementation: 1) reduces bacterial/viral infections; 2) decreases medical visits due to muscle
or joint problems; 3) diminishes episodes of heat exhaustion; 4) reduces muscle soreness; and
5) improves rifle scores in U.S. Marine recruits during basic training.
