# Fat and Insulin postworkout



## ParaManiac (Mar 20, 2007)

This is taken from an article by Alan Aragon on fat and insulin effects postworkout.

POST-EXERCISE

Effect on 24-hr Glycogen Resynthesis

A common recommendation in sports and fitness circles is to avoid or minimize fat intake immediately after training, a time popularly called the "anabolic window" or "window of opportunity". The fear of post-exercise fat is based on its ability to slow gastric emptying, and thus slow the release of glucose into circulation which in turn reduces insulin response and glycogen resynthesis. Is this a valid concern? First of all, exercise for varies in its ability to tap-out glycogen stores. Resistance training, as it's commonly done for strength, bodybuilding, or general fitness, is not glycogen-depleting in fed subjects on moderate-volume protocols. To illustrate this, Roy and Tarnopolsky observed 9 sets of 10 reps at 80% of 1 rep max to cause an average muscle glycogen decrease of 36%.16 It's important to note that subjects consumed 3 mixed meals approximately 3 hours apart leading into the trial, which was 3 hours after their 3rd meal. A fasted scenario would have been more glycogen-depleting, as would a more voluminous protocol. The interesting find of this trial is that there was no difference in glycogen synthesis rate between a mixed post-workout drink (66% carb, 23% prot, 11% fat) and a 100% carb drink. Both drinks had the same proportion of carb types, so that potential confounder was controlled.

In another example of the triviality of worrying about fat's inhibition of glycogenesis, Burke's team compared a control diet of 7g/kg of high-GI carbs with two experimental treatments consisting of the control diet plus a substantial amount of added fat (1.6g/kg) and protein (1.2g/kg), and a matched-energy diet which was the control diet with added carbs to equal the calories of the experimental treatments.17 Subjects trained for 2 hours at 75% VO2max, ending off the session with four 30-second sprints. Despite a high fat intake in the experimental group, no differences in muscle glycogen content were seen 24 hours after training compared to the low-fat groups.

Along these same lines, Fox and colleagues observed no difference in glycogen replenishment 24 hours after glycogen-depleting exercise despite the addition of 55g in the post-exercise meal and also in the two meals following it.18 Think about it, 165g of additional fat did not prevent the resynthesis of identical amounts of glycogen the next day. And yes, carbohydrate content was the same in both diets. So, unless you've trained to depletion, and are going to train the exact same muscles in another exhaustive event within 24 hours, concerns of post-exercise fat getting in the way of glycogen resynthesis is just plain silly - especially if your total daily fat intake isn't stupendously high to begin with.

Recently, an online forumite posed an interesting question - should omega-3 fatty acids be avoided post-exercise due to their anti-inflammatory properties which could potentially hinder protein synthesis? As a corollary, should arachidonic acid's pro-inflammatory properties be taken advantage of at this time? While omega-3 fatty acids are anti-inflammatory, they're also vaso-dilatory (increasing blood flow). Incidentally, they're also broncho-dilatory (increasing breathing capacity). So, whatever detriment they might have near exercise is likely neutralized by other factors. As for arachidonic acid supplementation, a recent trial saw a decrease in the inflammatory effect of exercise.19 Although it increased anaerobic sprint capacity, it had no effect on maximal strength or body composition. Alan Aragon's Research Review, January, 2008 - Inaugural Issue Page 4

Is It Necessary to "Spike" Insulin Post-workout?

Another concern of the fat-free-post-workout camp is the blunting of the insulin response. The rationale of maximizing the insulin response is to counteract the catabolic nature of the post-trained state, switching the hormonal milieu into an anabolic one, thus speeding recovery. Although this might benefit those who train fasted or semi-fasted, many don't realize that a pre-exercise meal (and in some cases the mid-exercise meal) is doing more than enough spiking of insulin levels for anticatabolic purposes.

It's an important objective to not only maximize muscle protein synthesis, but also minimize protein breakdown. However, the latter doesn't require a massive insulin spike, but rather just a touch beyond basal/resting levels. To illustrate this, Rennie & colleagues found that even during a sustained high blood level of amino acids, no further inhibition of muscle protein breakdown occurred beyond insulin elevation to approximately 15 μU/l,20 which is slightly above normal basal levels of 5-10 μU/l.

To reiterate, the pre-exercise meal can have profound effects on insulin levels that surpass the length of the training bout. Tipton's team found that as little as 6g essential amino acids + 35g sucrose taken immediately before exercise (45-50 minutes of resistance training) was enough to keep insulin elevated to roughly 4x above fasting levels 1-hour post-exercise.21 It took 2 hours post-exercise for insulin to return to resting levels. A similar insulin response was seen with 20g whey by itself taken immediately preworkout.22 If carbs were added to the pre-training protein, there would be yet a greater insulin response.

As far as solid food goes, Capaldo's team examined various metabolic effects during a five hour period after ingesting a meal composed of 75g carb (47%), 37g prot (26%), and 17g fat (27%).23 Although this study didn't examine training effects, this meal would make a nice post-workout meal due to its absolute (and proportional) amounts of protein and carbohydrate. The fat-fearing camp would warn against the meal's fat content interfering with the insulin response. However, this meal was able to raise insulin 3 times above fasting levels within 30 minutes of consumption. At the 60 minute mark, insulin was 5 times greater than fasting. At the 300 minute mark, insulin levels were still double the fasting level.

Elliot and colleagues compared the effect of fat-free milk, whole milk, and a higher dose of fat-free milk (to match the calories of the whole milk) taken 60 minutes post-resistance exercise.24 Whole milk was superior for increasing net protein balance. Interestingly, the calorie-matched dose of fat free milk containing 14.5g protein, versus 8.0g in the whole milk (an 81% advantage), but still got beaten. The investigators speculated over the possible mechanisms behind the outcome (insulin response, blood flow, subject response differences, fat content improving nitrogen retention), but end up dismissing each one in favor of concluding that further research is necessary to see if extra fat calories ingested with an amino acid source will increase muscle protein synthesis. Lingering questions notwithstanding, post-workout milkfat was the factor that clinched the victory - at least in overnight-fasted subjects.

To put another nail in the coffin of the insulin spiking objective, post-exercise glycogen resynthesis is biphasic.25 Unlike the subsequent "slow" phase which can last several hours, the initial "rapid" phase of glycogenesis lasting 30-60 minutes immediately post-exercise is not dependent upon insulin. Maximizing post-workout hyperinsulinemia may be beneficial for athletes with more than a single exhaustive endurance-containing training bout separated by less than approximately 8 hours, but in all other cases, the benefit in "spiking" insulin is nil.

In line with this theme, interesting research has surfaced in recent years challenging the idea that highly glycemic (and thus insulinemic) carbohydrates taken post-workout are the optimal for recovery. Erith's team found no difference between post-exercise high- and low-glycemic index (GI) carbohydrate intake on exercise performance the following day.26 In a similar study, Stevenson's team actually saw better next-day performance in subjects who consumed low-GI post-exercise carbohydrate than those who consumed high-GI post-exercise carbohydrate.27

SUMMARY & APPLICATION

Hierarchy of importance, fat loading

Of primary importance is total amount of the macronutrients by the end of the day. Timing of nutrients is secondary, since there's typically a constant absorptive overlap between meals in a well-constructed diet.

Much of the existing sports nutrition research is done on endurance athletes, so an inevitable degree of extrapolation is necessary for those involved with non-endurance activities.

2-6 days of high fat intake (~60-70% of total kcals) can result in "fat adaptation", a state increased fat oxidation during training, and in conditioned individuals, at rest as well.

Becoming "fat adapted" offers little to no ergogenic benefit. Adding a final-day-day carb load to a fat loading phase hasn't proven to remedy its lack of performance effect.

Impaired sprinting ability resulting from fat loading carries negative implications for its utility in competitive endurance and ultra-endurance events, since they include intermittent bouts of increased intensity. Fat loading carries more risk than benefit, and can safely be avoided.

Single pre-loads

MCT preloads do not increase performance or decrease glycogen breakdown during training. The scant data on LCT preloads indicate the same lack of benefit.

During exercise

During exercise, MCT doesn't enhance performance, and can cause gastrointestinal upset, decreasing performance. For these reasons, LCT and MCT can safely be nixed.

Post-exercise

Preliminary evidence suggests the potential for arachidonic

acid to enhance anaerobic capacity (sprints in particular). However, it had no effect on strength or body composition.

Alan Aragon's Research Review, January, 2008 - Inaugural Issue Page 5

High amounts of post-exercise fat (up to approximately 165g) do not reduce 24-hour glycogen synthesis. Thus, those who do not train the same muscles to glycogen depletion (or near-depletion) more than once a day shouldn't be concerned with a normal fat intake, even in the post-workout period.

Is spiking insulin necessary post-workout? Generally not.

No greater inhibition of muscle protein breakdown has been seen beyond insulin elevation to approximately 15 μU/l, which is slightly above resting/basal levels of 5-10 μU/l.

In one study, whole milk was superior for increasing net protein balance post-workout, despite the calorie-matched dose of fat free milk containing 81% more protein.

The initial 30-60 minute "rapid" phase of glycogenesis immediately post-exercise is not dependent upon insulin.

There's no need to attempt to spike insulin for recovery purposes since maximal effects are seen at minimal elevations. Simply getting enough total substrate surrounding the training bout suffices, at least within the context of a 24-hour separation between exhaustive training of the same muscles. Multiple depleting endurance-type bouts per day (i.e., < 8 hours between bouts) may be the exception to this rule.

On a related tangent, it's been commonly recommended to maximize post-exercise hyperglycemia and hyperinsulinemia by consuming high-GI carbohydrates. However, this strategy has been seen to offer no benefit on next-day performance, and one recent study even saw endurance impairment.

REFERENCES

1. Zderic TW, et al. High-fat diet elevates resting intramuscular triglyceride concentration and whole body lipolysis during exercise. Am J Physiol Endocrinol Metab. 2004 Feb;286(2):E217-25. [Medline]

2. Burke LM, et al. Effect of fat adaptation and carbohydrate restoration on metabolism and performance during prolonged cycling. J Appl Physiol. 2000 Dec;89(6):2413-21. [Medline]

3. Carey AL, et al. Effects of fat adaptation and carbohydrate restoration on prolonged endurance exercise. J Appl Physiol. 2001 Jul;91(1):115-22. [Medline]

4. Phinney SD, et al. The human metabolic response to chronic ketosis without caloric restriction: preservation of submaximal exercise capability with reduced carbohydrate oxidation. Metabolism. 1983 Aug;32(8):769-76. [Medline]

5. Burke LM, et al. Adaptations to short-term high-fat diet persist during exercise despite high carbohydrate availability. 2002 Jan;34(1):83-91. [Medline]

6. Hansen KC, et al. Exercise increases the proportion of fat utilization during short-term consumption of a high-fat diet. Am J Clin Nutr. 2007 Jan;85(1):109-16. [Medline]

7. Havemann L, et al. Fat adaptation followed by carbohydrate loading compromises high-intensity sprint performance. J Appl Physiol. 2006 Jan;100(1):194-202. [Medline]

8. Noakes T. Fat adaptation and prolonged exercise performance. J Appl Physiol. 2004 Mar;96(3):1243; author reply 1243-4. [Medline]

9. Burke LM, Kiens B. "Fat adaptation" for athletic performance: the nail in the coffin? J Appl Physiol. 2006 Jan;100(1):7-8. [Medline]

10. Nosaka N, et al. Effects of margarine containing medium-chain triacylglycerols on body fat reduction in humans. J Atheroscler Thromb. 2003;10(5):290-8. [Medline]

11. Kosai M, et al. Effect of dietary medium- and long-chain triacylglycerols (MLCT) on accumulation of body fat in healthy humans. Asia Pac J Clin Nutr. 2003;12(2):151-60. [Medline]

12. Jeukendrup AE, Adred S. Fat supplementation, health, and endurance performance. Nutrition. 2004 Jul-Aug;20(7-8):678-88. [Medline]

13. Horowitz JF, Coyle EF. Metabolic responses to preexercise meals containing various carbohydrates and fat. Am J Clin Nutr. 1993 Aug;58(2):235-41. [Medline]

14. Cappon JP, et al. Acute effects of high fat and high glucose meals on the growth hormone response to exercise. J Clin Endocrinol Metab. 1993 Jun;76(6):1418-22. [Medline]

15. Goedecke JH, et al. The effects of medium-chain triacylglycerol and carbohydrate ingestion on ultra-endurance exercise performance. Int J Sport Nutr Exerc Metab. 2005 Feb;15(1):15- 27. [Medline]

16. Roy BD, Tarnopolsky MA. Influence of differing macronutrient intakes on muscle glycogen resynthesis after resistance exercise. J Appl Physiol. 1998 Mar;84(3):890-6. [Medline]

17. Burke LM, et al. Effect of coingestion of fat and protein with carbohydrate feedings on muscle glycogen storage. J Appl Physiol. 1995 Jun;78(6):2187-92. [Medline]

18. Fox AK, et al. Adding fat calories to meals after exercise does not alter glucose tolerance. J Appl Physiol. 2004 Jul;97(1):11-6. [Medline]

19. Roberts MD, et al. Effects of arachidonic acid supplementation on training adaptations in resistance-trained males. Int Soc Sports Nutr. 2007 Nov 28;4(1):21. [Medline]

20. Rennie MJ, et al. Branched-chain amino acids as fuels and anabolic signals in human muscle. J Nutr. 2006 Jan;136(1 Suppl):264S-8S. [Medline]

21. Tipton KD, et al. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E197-206. [Medline]

22. Tipton KD, et al. Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise. Am J Physiol Endocrinol Metab. 2007 Jan;292(1):E71-6. [Medline]

23. Capaldo B, et al. Splanchnic and leg substrate exchange after ingestion of a natural mixed meal in humans. Diabetes. 1999 May;48(5):958-66. [Medline]

24. Elliot TA, et al. Milk ingestion stimulates net muscle protein synthesis following resistance exercise. Med Sci Sports Exerc. 2006 Apr;38(4):667-74. [Medline]

25. Jentjens R, Jeukendrup A. Determinants of post-exercise glycogen synthesis during short-term recovery. Sports Med. 2003;33(2):117-44. [Medline]

26. Erith S, et al. The effect of high carbohydrate meals with different glycemic indices on recovery of performance during prolonged intermittent high-intensity shuttle running. Int J Sport Nutr Exerc Metab. 2006 Aug;16(4):393-404. [Medline]

27. Stevenson E. Improved recovery from prolonged exercise following the consumption of low glycemic index carbohydrate meals. Int J Sport Nutr Exerc Metab. 2005 Aug;15(4):333-49. [Medline]

Alan Aragon's Research Review, January, 2008 - Inaugural Issue Page 6

Link to full Article - http://user210805.websitewizard.com/...R-Jan-2008.pdf


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## pitbull1436114521 (Dec 19, 2006)

Not a direct response to the article.

But just over 5-6 months back i drop my PWO drink for a whole meal.

In the past used various brand PWO drinks, Glucose, malto and WMS mixes with a varity of different type proteins.

I now use 65g Oats, 15g Raisins, 1 scoop whey and 1 scoop pro-pep mix it up with cold water couple hours before training then just eat once i get in the car outside the gym. Marco break down is 50g Carbs / 50g Protein / 10g fat.

Now this is just based on my opinion but i have't noticed a single difference in recovery etc since the swap.

If anything i prefer it! fills me up without the bloat but not that i can't eat my chicken and rice meal 1-1.5 hours later.

Just my 2 pence worth

Sam


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## MXD (Jan 23, 2008)

Excellent article, repped.


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## Bigger&amp;Stronger (Feb 26, 2008)

Cheers for the informative articles mate, Alan always seems to have his head screwed on when it comes to sports nutrition.


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## 13stonetarget (Aug 21, 2007)

Interesting article - thanks


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## hackskii (Jul 27, 2003)

What a fantastic find, oh man, what a jewel of a read, thank you so much for posting that.

I would like to comment on a couple of things that jumps out at me.



ParaManiac said:


> should arachidonic acid's pro-inflammatory properties be taken advantage of at this time? While omega-3 fatty acids are anti-inflammatory, they're also vaso-dilatory (increasing blood flow). Incidentally, they're also broncho-dilatory (increasing breathing capacity). So, whatever detriment they might have near exercise is likely neutralized by other factors.


I was avoiding taking my fish oils post wokout, for two reasons, which both now are refuted. One was slowing digestion (not so now it seems), and the other was for its anti-inflammation properties (now we know that isn't an issue either).

So, I will now take my fish oils after a workout, hell I am almost 50 anyway and am stiffer than ever in my life&#8230;&#8230;Beautiful find here, brilliant.



ParaManiac said:


> As for arachidonic acid supplementation, a recent trial saw a decrease in the inflammatory effect of exercise.19 Although it increased anaerobic sprint capacity, it had no effect on maximal strength or body composition. Alan Aragon's Research Review, January, 2008 - Inaugural Issue Page 4


So much for William Llewellyn's suggesting a couple of pounds a week muscle gain from X-Factor.



ParaManiac said:


> Tipton's team found that as little as 6g essential amino acids + 35g sucrose taken immediately before exercise (45-50 minutes of resistance training) was enough to keep insulin elevated to roughly 4x above fasting levels 1-hour post-exercise.21 It took 2 hours post-exercise for insulin to return to resting levels. A similar insulin response was seen with 20g whey by itself taken immediately preworkout.22 If carbs were added to the pre-training protein, there would be yet a greater insulin response.


Fantastic, I didn't know it was such a small amount that did this.



ParaManiac said:


> Unlike the subsequent "slow" phase which can last several hours, the initial "rapid" phase of glycogenesis lasting 30-60 minutes immediately post-exercise is not dependent upon insulin. Maximizing post-workout hyperinsulinemia may be beneficial for athletes with more than a single exhaustive endurance-containing training bout separated by less than approximately 8 hours, but in all other cases, the benefit in "spiking" insulin is nil.


This is awesome, I never played into the high glycemic PWO and I have suggested before that PWO we are insulin sensitive anyway. Not to mention simple sugars push us more to insulin resistance than other complex carbohydrate sources.



ParaManiac said:


> Erith's team found no difference between post-exercise high- and low-glycemic index (GI) carbohydrate intake on exercise performance the following day.26 In a similar study, Stevenson's team actually saw better next-day performance in subjects who consumed low-GI post-exercise carbohydrate than those who consumed high-GI post-exercise carbohydrate.27


This sums it up very nicely.

This is an awesome post, thanks a lot reps.....


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## ParaManiac (Mar 20, 2007)

Thanks Scott,i posted earlier,in response to Sportsdoc,regards my choice of Pwo carb which also supports the none sugar route.

Like i posted there though,imo,this is a very individually based approach and not the best method for everyone. 

Alan Aragon posts some great stuff

http://www.alanaragon.com/


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