Wednesday, January 30, 2008

Eating Carbs after your workout reduces the fat burning effect?

If you want to maximise the fat burning effect of effect of exercise, what should you eat after a workout? This study - and the full paper is currently available here - seems to indicate that you should keep away from a carbohydrate rich meal. It is a really interesting paper to read and what I get from it is that having a carb rich meal after a workout blunts the fat burning effect generated by the exercise. Have a read - see what you think.

Devany gives another reason not to eat carbs after the workout

Does prior acute exercise affect postexercise substrate oxidation in response to a high carbohydrate meal?

BACKGROUND: Consumption of a mixed meal increases postprandial carbohydrate utilization and decreases fat oxidation. On the other hand, acute endurance exercise increases fat oxidation and decreases carbohydrate utilization during the post-exercise recovery period. It is possible that the resulting post-exercise increase in circulating nonesterified fatty acids could attenuate the ability of ingested carbohydrate to inhibit lipid oxidation. The purpose of this study was to determine whether prior exercise attenuates the usual meal-induced decline in lipid oxidation.
METHODS: Six healthy, physically active young subjects (x age = 26.3 years, 4 males, 2 females) completed three treatments in random order after a ~10 h fast: (a) Exercise/ Carbohydrate (Ex/CHO): subjects completed a bout of exercise at 70% VO2peak (targeted net energy cost of 400 kcals), followed by consumption of a carbohydrate-rich meal; (b) Exercise/Placebo (Ex/Placebo): subjects completed an identical bout of exercise followed by consumption of a placebo; and (c) No Exercise/Carbohydrate (NoEx/CHO): subjects sat quietly rather than exercising and then consumed the carbohydrate-rich meal. Blood samples were obtained before and during the postprandial period to determine plasma glucose, insulin, and non-esterified fatty acids (NEFA). Respiratory gas exchange measures were used to estimate rates of fat and carbohydrate oxidation.
RESULTS: Plasma NEFA were approximately two-fold higher immediately following the two exercise conditions compared to the no-exercise condition, while meal consumption significantly increased insulin and glucose in both Ex/CHO and NoEx/CHO. NEFA concentrations fell rapidly during the 2-h postprandial period, but remained higher compared to the NoEx/CHO treatment. Carbohydrate oxidation increased rapidly and fat oxidation decreased in response to the meal, with no differences in the rates of carbohydrate and fat oxidation during recovery between the Ex/CHO and NoEx/CHO conditions.
CONCLUSION: The plasma NEFA concentration is increased during the post exercise period, which is associated with elevated fat oxidation when no meal is consumed. However, when a mixed meal is consumed immediately following exercise, the initially elevated plasma NEFA concentration decreases rapidly, and postexercise fat oxidation during this 2-h postexercise, postprandial period is no higher than that of the 2-h postprandial period without prior exercise.


Viagra said...

just one question, what is the reason to make workout and don't burn fat? I mean yes of course for health, but most of the people do it workout with anothers objetives, to look well.

Buy Generic Cialis said...

my silly brother, you can't see more than your eyes can see, right? this is for propuse, there's people that need only feel good, and don't lose any gramme of weight.