Is nutrient timing important?

Nutrient timing is based upon the premise that providing nutrients— primarily protein and carbohydrate— at a certain time in relation to an exercise bout will lead to greater adaptations to training, compared to getting your nutrition haphazardly. Most believers are convinced the ideal time is after intense training.

A recent review and position paper by the International Society of Sports Nutrition (ISSN) looked at nutrient timing in relation to exercise performance, glycogen repletion, and training adaptations (body composition, muscle mass, and muscle fiber size).1 One conclusion was that ingesting a carb + protein supplement after training promotes greater increases in strength and more favorable changes in lean mass and fat mass.

Nutrient timing has been embraced by most everyone as crucial, but is it?

Most of us in the gym can’t wait to grab the post-workout supplement after our workout. We’ve read it’s critical immediately following our workout, or is it? Let’s look at a couple studies that examined nutrient timing in athletes and novice fitness enthusiasts.

One study took 23 non-competitive, young (early 20s) Australian bodybuilders with an average of three years of experience and matched them for max strength (1 rep max; 1RM). Half of the group then took a carb + protein + creatine monohydrate supplement (40 percent protein from whey protein isolate, 43 percent dextrose, and 7 percent creatine monohydrate) just before and just after training (four personal training supervised sessions in the mid-late afternoon/week for 10 weeks). The other half took the same supplement twice daily on training days (same training regimen as pre-post group), yet before breakfast and before sleep (a.m.-p.m.) on the same training days.

If you accept that the subjects in the a.m.-p.m. group didn’t eat or drink anything for 1-2 hours after they trained— for 10 weeks— then the results for the pre-post group are distinctive: greater lean mass gains and fat mass drops; greater 1RM in squats and bench press; bigger muscle fibers and more contractile protein (not just muscle protein); higher muscle creatine and glycogen content. Again, this is the only study using resistance-trained subjects AND where timing is compared. Admirably, the lead author of the study disclosed that he is a consultant to AST (disclosure is not common— trust me).

Another study looked at 30 northeast American college football players (late teens/early 20s), with an average of almost six years of resistance training, and three powerlifters were assigned to either 1) take a liquid protein supplement pre-post, 2) take it in the a.m.-p.m., or 3) take a placebo supplement. All three groups followed a 10-week supervised training regimen (four sessions/week). The liquid protein supplement delivered 42 grams of protein (enzymatically predigested beef collagen, whey protein isolate, casein) and 2 grams of carbs.3 Unlike the prior study, the subjects took the supplement every day during the 10 weeks.

After 10 weeks no significant difference in body comp or any measure of squat or bench press performance was seen between any of the groups, including the placebo group. Modest improvements in strength and power were seen in the two supplemented groups, but they were not significantly greater than the placebo group.

Why the different results between the only two studies done in resistance-trained subjects putting chronic nutrient timing in the hot seat? The first study used bodybuilders who took in about 30 percent more calories (mostly from carbs, not including the supplement), weighed less, and were much leaner. The bodybuilders also were taking in about 10-25 percent more protein at the beginning of the study than the football players. The bodybuilders also supplemented with carbs and creatine monohydrate in addition to protein.

Despite the football players/powerlifters getting the protein supplement every day for 10 weeks, there was no difference. This is not a revelation— more protein does not automatically beget more muscle mass. What may be the revelation is that supplemental calories/carbs may make a difference when protein is at the ceiling of intakes.

As it stands, nutrient timing-mediated muscle and strength gains in resistance-trained men is superior for whey protein isolate + dextrose + creatine monohydrate.

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Anthony Almada (B.Sc., M.Sc.) has worked within the dietary supplement industry since 1975. He has a B.Sc. in physiology and nutritional biochemistry minor from California State University, Long Beach, and an M.Sc. from Berkeley. He has been a co-investigator on over 60 university clinical trials, ranging from arthritis to muscle building and fat loss. Anthony Almada is a member of the executive board of ISSN, and is a fellow of the ISSN.

References:
1. Kerksick C, et al. International society of sports nutrition position stand: nutrient timing. J Int Soc Sports Nutr, 2008;5:17.
2. Cribb PJ, Hayes A: Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy. Med Sci Sports Exerc, 2006;38:1918-25.
3. Hoffman JR, et al. Effect of protein supplement timing on strength, power and body compositional changes in resistance-trained men. Int J Sport Nutr Exerc Metab, (published online advance of print; accessed 13 March 2009).

Source: http://www.musculardevelopment.com/component/content/article/135-supplements/3364-on-time-off-target-nutrient-timing-for-the-md-reader-by-anthony-almada.html

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