Rethinking post workout nutrition - Do you really need the carbs?

[adam adkins]

Post workout carbs are just about as well-established as any nutritional tenet. Nutritional guru Robb Wolf recommends taking in half of your daily carbs post workout. But is any of it really necessary? And, perhaps more importantly, are these post-workout carbs actaully counterproductive?

In the latest addition of Powerlifting USA, Louis Simmons takes the unique stance that "eliminating post trianing carbs can have added anabolic and fat burning effects." Louis argues that "an increased availability of dietary carbohydrate in the hours after exercise and the resultant increase in muscle glycogen resynthesis reverses the exercise-induced increase in insulin sensitivity."

This is critical, Louis argues, because, "by increasing insuling levels and not providing carbs you shunt your body's metabolism to the use of more fatty acids for energy while at the same time keeping muscle glycogen levels below saturation and amino acid influx and protein synthesis elevated for a prolonged period of time."

Louis concludes that, "if no carbohydrates are given post exercise the muscle will maintain a capacity to fully compensate or supercompensate glycogen until enough carbs are either available through diet or by gluconeogenesis to fill the glycogen stores as much as possible." Finally, Louis states, "The bottom line is that the key to maximizing body composition, and to increase performance in fat adaptive athletes is to keep carbs low and energy and protein intake high for several hours or even more after exercise."

Louis's argument seems to follow the logic of James Fitzgerald of OTP how prescribes post workout carb intake based upon the athletes body composition with the leanest receiving the most carbs. But with that said, I have heard this argument in strikingly few places. Louis article is the first I have seen to detail the no post-workout carb plan in such detail. On here, even the most diehard Paleo followers cram in as much post-workout carbs as possible.

So what say you?

(See the full article in Powerlifting USA - no link sorry)

[Renee Lee]

Louis's argument seems to follow the logic of James Fitzgerald of OTP how prescribes post workout carb intake based upon the athletes body composition with the leanest receiving the most carbs.

I think this about sums it up. Robb Wolf also says to not worry about post workout nutrition until you reach your desired level of leaness.

I don't know the biochem behind it...but if Robb says it, I'm apt to believe it.

[Greg Privitera]

I don't eat carbs post workout, but load up on protein and carbs before/during (during if its a strength workout).

[Steven Low]

It depends on your goals....

[Jason Peacock]

That all matches what I learned from Robb's PWO discussion - if you're lean, then include carbs for performance. If you're not lean then skip the carbs to promote fat burning, and don't worry about the performance until you're lean.

From what I understand of Simmons, that's the same advice - adding carbs will stop the fat burning, which is only good if you're already lean.

[Eric Montgomery]

Robb's post-WOD nutrition posts also mention that low carb may have anabolic effects and help maintain insulin sensitivity for a longer period of time, and is the way to go if you're not already as lean as you want to be. He goes into the hows and whys of both low and high carb in this post (WFS).

The argument for high carb (aside from helping to pump nutrients into your muscles fast) is that it refills muscle glycogen that gets burned off during an intense metcon, which is mainly important if you're doing a two-a-day. If you've got a full day to recover before your next workout a high amount of carbs isn't as important.

[Shane Skowron]

If you're like me and have another workout to do in a few hours, then yes, you really do need the carbs.

[Leonid Soubbotine]

No carbs or very low amount is fine for performance even while doing multiple training sessions a day.

[Darryl Shaw]

Louis is right that fat oxidation is increased if glycogen stores are depleted through exercise (link). Deliberately maintaining reduced glycogen stores in the hope that you'll lose weight (fat) will prove counterproductive for an athlete however as reduced glycogen stores impair your ability to train and perform at high intensities which will result in a loss of training adaptations as well as reducing the number of calories burned through exercise.

The Effect of Carbohydrates and Fats on 24 Hour Nitrogen Balance.

As has been discussed, energy has a tremendous nitrogen sparing effect [34]. However, a related topic concerns the differential effects of fats and carbohydrates on nitrogen balance. In this context, McCarger [83] investigated the effects of a high carbohydrate or high fat diet on nitrogen retention, substrate utilization, and serum hormone concentrations in six healthy male participants. The diets were administered at maintenance and at 75% of maintenance calories. Results indicated that the high fat diet produced slightly greater nitrogen retention in the 75% restricted diet than the high carbohydrate diet, while no differences existed between diets at maintenance. Results such as this have led Millward to suggest that "for now energy intakes can be considered independently from the composition of that energy as determinants of NB, thus simplifying the issue [34]." However, these results need to be replicated; particularly, in the context of exercise training.

Carbohydrates and Fats in Resistance training exercise.
While carbohydrates and fats may spare nitrogen in a similar manner, it is important to recognize that carbohydrates are critical for high intensity exercise. As an illustration Jacobs et al. [84] investigated the effect of depleting muscle fibers of glycogen on strength levels. It was found that glycogen depletion in both fast and slow fiber types in the vastus lateralis was associated with impaired maximal muscular strength produced during a single dynamic contraction, as well as with increased muscle fatigue patterns. Further, it has been well established that a decrease in intensity can cause a significant loss of adaptation [43,85-88]. These results suggest that a decrease in carbohydrates may indirectly decrease muscle tissue, or impair further adaptations.

Interaction between carbohydrates and protein/amino acid intake.
Koopman and colleagues [89] investigated the effects of carbohydrate (0.3 g per kg-per hour) (CHO), carbohydrate and protein (0.2 g per kg-h) (CHO-PRO) and carbohydrates, protein and leucine (0.1 g per kg-h) (CHO-PROL) on net protein balance, and amino acid oxidation rates. Results indicated that net balance was negative in the CHO condition, and positive in the CHO-PRO and CHO-PROL conditions, with the latter attaining the highest values. These results paralleled plasma insulin concentrations, with insulin being highest in the CHO-PROL condition, intermediate in the CHO-PRO condition, and lowest in the CHO condition. The net balance was improved through increased protein synthesis and decreased protein breakdown in the CHO-PROL condition relative to the other two conditions. Further protein oxidation was lowest in the CHO-PROL condition. The rationale may be that leucine intake enhances insulin secretion [89], and independently increases protein synthesis [90,91]. It is generally thought that insulin enhances protein balance through hindering protein degradation [40,92], which was supported by this study.

However, the role of insulin in stimulating protein synthesis is in debate [89]. In vitro studies [93-95] have supported insulin's role in regulating protein synthesis, while a number of in vivo studies have shown discrepancies in protein synthesis [96]. As an illustration Biolo et al. [92] found that insulin infusion increased protein synthesis at rest, but not after resistance training exercise. The authors concluded that it was the decreased amino acid availability which depressed the stimulatory effect of insulin. This was supported by Biolo et al. [97] when they found that maintained amino acid levels in the presence of hyperinsulemia increased protein synthesis. Further, Hiller and colleagues [96] suggested that discrepancies seen between in vitro studies and in vivo studies centered around plasma concentrations of insulin. To test this question, Hiller et al. [96] raised plasma insulin levels to concentrations similar to studies conducted in vitro, while maintaining amino acid concentrations. It was found that hyperinsulemia increased protein synthesis greatly. Therefore, mechanisms which enhance the insulin response to food may enhance protein accretion. The efficacy of combining carbohydrates and protein on insulin secretion was demonstrated by Ivy et al. [98] who found that the combined effects of protein and a high glycemic carbohydrate were greater on stimulating insulin secretion than their independent effects.

Summary of the effect of carbohydrates and fats on protein balance.
In summary it appears that both carbohydrates and proteins have similar nitrogen sparing effects [34,83]. In this context it may be advisable to increase fats when carbohydrates are lowered. However because carbohydrates are critical to athletic performance [84] the athlete should be conscious of decreased intensity and performance with decreased carbohydrate intakes. Finally, there appears to be an interaction effect between protein and carbohydrates in stimulating insulin secretion [98-100]. This latter effect may be beneficial when manipulated for protein accretion purposes.

http://www.jissn.com/content/3/1/7

*All links wfs*

[Leonid Soubbotine]

Darryl - the glitch with the paper you published is this:

These results suggest that a decrease in carbohydrates may indirectly decrease muscle tissue, or impair further adaptations.

because carbohydrates are critical to athletic performance [84] the athlete should be conscious of decreased intensity and performance with decreased carbohydrate intakes

That research paper is based on a theory that CHO are critical. Yet we know that being very low carb is indeed anabolic & can tremendously improve strength gains. That proves that article obsolete for it's based on a theory that seems to be quite wrong/unnecessary, at least in the case of strength training (which Louie is an obvious expert at).