Chocolate milk does an athlete’s body good? The latest research on a childhood fave.

You’ve heard him: those porn-like grunts; the grating screams of chains dog-piling on top of each other; the head-butting of tons of heavy iron against…more tons of heavy iron; blaring beats at next-door-night-club decibel levels advertising his music taste; even the almost-audible throbbing of his veins painting his body like a corrugated road-map. It’s “that guy” at the gym: conductor of Cacophonous Symphony, demanding you to listen, hoping that you’ll envy, and expecting that you’ll judge.

Enough people have slammed on “that guy.” He puts tuna in his oatmeal. He deadlifts his car for fun. He brings chicken breasts to movies as snacks. And he wouldn’t be caught dead in the gym without his beloved protein shake, either the home-spun version found in some measuring Tupperware-like bottle, or the Muscle Milks that are typically sold at the gym’s front desk.

But can we learn something from “that guy”? And what would happen if he saved 3.75 on his Muscle Milk or 44.98 on his Whey protein powder and just rolled with some 99 cent Moo-tastic chocolate milk instead (oh, the image-detonating horrors!) And while we’re at it, what’s up with chocolate milk for the rest of us who don’t bench press the weight of an adolescent polar bear?

But first, let’s talk about the window…

We all have a “window of opportunity” after we workout. Whether you’re tossing around kettlebells, hitting up a spin class, or going on a long run, you have a period of time after you finish where your body has enhanced nutrient uptake, and these nutrients are used to replenish what you drained and restore some of the muscle tissue you tore down (1).

What’s to restore?  First, you drained some of your glycogen (or carbohydrate) stores. Muscle glycogen is the primary fuel source during high-intensity and endurance exercise. When and whether or not you refill this store of energy after your workout is a huge factor in your body’s recovery (2).

In addition to depleting carb stores, if you had a high intensity workout you probably incurred some sort of exercise-induced muscle damage, too; this will either lead to DOMS (Delayed Onset Muscle Soreness), or at the very least you will have decreased energy and performance if the markers of muscle breakdown remain high.

So now that I broke my body down, what do I do? 

Sidle up to the largest guy in the gym, stealth grab his protein shake while he’s bench pressing, chug it while sprinting far away, and enter a witness protection program.

Or, if your goal is building fitness and performance, you should maximize glycogen re-synthesis by eating or drinking carbohydrates within 30-60 minutes after you exercise. This means you will recover quicker and be ready for the next workout sooner.  How much do you eat? If you are an elite athlete that needs to perform later that day or the next, 1.0-1.2 grams of carbs / kg of body weight / hour for the first 4 hours.  If you’re not an elite athlete, but someone who is training for fitness and performance, 1.0 -1.2 grams of carbs / kg body weight within the first hour is fine (3).

Carbs? But “that guy” appears to be downing shots of processed muscle meat from Siberian tigers! What about protein?

He’s probably going way overboard. You do need more protein for heavy, heavy lifting and muscle building, but not that much (another topic for another day). The research is clear that carbs after workouts helps recovery and performance (4). Protein can theoretically help to minimize muscle breakdown, and capitalize on the increased protein-making that happens after a workout. Studies show that the carb to protein ratio for refueling should be either 3-1 or 4-1. This means if you are consuming 60 grams of carbs, you should add about 15-20 grams of protein.

How stressful! What if I don’t eat in time?! Does the window close forever? Does it make my workout completely useless?!  

No. I do know people who would drive over kittens if necessary to reach some sort of food source within 30 minutes after their workout. Save the kittens.  The metaphoric window does not close, the rate at which you can use the fuel to aid shorter recovery simply decreases. Your workout is not wasted or useless if you don’t eat; it just is better if you can consume something within an hour, and you’ll have more power the next time you are active, as well.  If you wait 2 hours to eat, for example, your glycogen stores will be 45% lower at the 4-hour mark compared to eating immediately after your workout.

When are you going to talk about chocolate milk?!

Now! Lots of studies have been investigating post-exercise refueling using chocolate milk, a low-cost and highly nutritious alternative to expensive gym drinks.

Why chocolate milk?

Chocolate milk has close to the optimal ratio of carbs to protein. (Regular milk has a 2:1 ratio, and this higher amount of protein compared to the carbohydrates may slow the absorption through slower stomach-emptying rates, which is less than perfect when trying to refuel!) It has 12 grams of lactose (natural milk sugar) and some sucrose from the chocolate to fill those glycogen stores.  Chocolate milk also has high quality protein; it has whey protein, which is quickly absorbed and helps enhance muscle building.  It also has casein, a protein that is absorbed much more slowly, so there are levels of amino acids in your blood hours later to theoretically help reduce muscle breakdown. Milk also has lots of leucine, a branch chain amino acid that helps with making proteins and muscle metabolism. When compared to many electrolyte sports drinks, chocolate milk has lower sodium, but higher calcium and potassium, which get depleted during high sweat sessions. Finally, it has Vitamin D, and even Omega-3s, which are good things we’ll talk about another day.

So it’s good! Is it better than Muscle Milk?

It’s not clear that it’s better, but it’s at least just as good.  It seems that milk itself does do a better job at rehydrating than equal amounts of water or carb + electrolyte drinks (5). Studies either found chocolate milk to be better or no different than a carb or carb + protein drink for glycogen synthesis and muscle recovery. (6). When comparing subsequent performance, or time to exhaustion on the next workout, chocolate milk may provide more, but at least similar, performance benefits when compared with carb only or other carb + protein drinks.

Why can’t you just say yes or no?!

Because the studies use different measures, exercises, timing, study populations, etc when comparing milk to other similar drinks. Overall, it seems that compared to other sports drinks with similar carb to protein ratios, it may or may not be better, but it is at least just as good as the more expensive counterparts. Also, these other sports drinks sometimes come overly fortified or made with additives that may not be as healthy.

Geez, what’s the bottom line already?

If you aren’t lactose intolerant, as a recovery drink for your intense workouts, chocolate milk is at least as good, and much more natural, than other sports beverages out there.

So next time you see “that guy,” tell him he could save some dough by having some TruMoo instead.  He can pour it into a different container to save face.

Marily O

MS, RD, PhD

PS- The hope is that none of those guys were offended during the reading of this blog. They are awesome and don’t mind the stereotypes. 🙂

Footnotes

1. Scientists think that the increase in glycogen synthesis 2-4 hours after exercise may be due to more glycogen synthase (the “builder” enzyme) and exercise-induced increases in insulin sensitivity.

2. How much of the glycogen stores you use depends on the type, duration, and intensity of the exercise session; for example, after 6 seconds of all out exercise it has been reported that quadriceps’ glycogen stores had depleted by 14%!  Your glycogen stores and depletion time also depend on your diet leading up to the exercise, for example what percentage of your diet is carbohydrates, or if you are eating a fewer number of calories than you need to maintain weight.  Finally, the overall storage capacity and time to depletion can depend on how trained you are. Untrained individuals use more of their carbohydrate stores than trained individuals, who use more Free Fatty Acids. This does NOT mean that trained individuals are “burning fat”—losing adipose tissue is about total calories burned, not really what tissue it comes from. Hence the myth of the “fat-burning zone” is truly a myth. More on that in a future blog post if you are interested.  But to point, the trained individuals not only use a lower percentage of glycogen early in the workout, but have twice as much stored glycogen as untrained individuals to start with. Therefore the time to depletion for trained individuals is longer.

3. So for 130 lb person, divide by 2.2 to get kgs of bodyweight. That gives about 60 – 71 grams of carbohydrates, which is about 240 calories. For a 165 lb person, that’s about 70-90 grams. 

4. There is a debate over whether adding protein helps, but I won’t go into that here.  Some studies show improved performance (or time to exhaustion upon your next workout) when consuming a source of carbohydrates plus some protein during you window compared to consuming carbohydrates only, but other studies show no difference. It makes biochemical sense that protein would be a nice addition, because it could ostensibly attenuate some of the muscle damage by providing a building block for muscle reconstruction; at the very least, protein can be used to make glucose, so it can serve as a glycogen replenisher as well. My opinion is that for workouts that really break down your muscles, such as high intensity intervals, long endurance runs, or heavy weight lifting, it is necessary.

5. This study showed those drinking chocolate milk after a hard workout peed less over the 5 hours even though they had the same amount of liquid! This indicates that the fluids were actually getting into the cells rather than just the bloodstream. The authors explained it by the potassium levels in the milk, which could have affected the fluid absorption.

6. I’m not aware of a study comparing an isocaloric amount of another recovery drink with the same amount of carbs and protein as chocolate milk and taking muscle biopsies to see how it helps breakdown.

Sources:

A really excellent and up-to-date review of the studies about recovering post-exercise can be found here:

Pritchett, K.L., Prtichett, R.C., & Bishop, P. (2011). Nutritional strategies for post-exercise recovery: A review. South African Journal of Sports Medicine, 23(1), 20-25.

More Chocolate milk and post-exercise recovery reviews of research / studies:

Saunders, M.J. (2011). Carbohydrate-Protein intake and recovery from endurance exercise: Is chocolate milk the answer? Current Sports Medicine Reports, 10(4), 203-210.

Lunn, W.R., Pasiakos, S.M., Colletto, M.R., Karfonta, K.E., Carbone, J.W., Anderson, J.M., & Rodriguez, N.R. (2012). Chocolate milk and endurance exercise recovery: protein balance, glycogen, and performance. Medicine and Science in Sports and Exercise, 44(4), 682-691.

Shirreffs, S.M., Watson, P., & Maughan, R.J. (2007). Milk as an effective post-exercise rehydration drink. British Journal of Nutrition, 98, 173-80.

Pritchett, K., Bishop. P., Pritchett, R., et al. (2009). Acute effects of chocolate milk and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance. Applied Physiology, Nutrition, & Metabolism, 34, 1017-22.

The timing of milk supplement for attenuating exercise-induced muscle damage (although the only comparison groups were before workout, immediately after, and 24 hours after):

Cockburn, E., Stevenson, E. Hayes, P.R.,  Robson-Ansley, P., Howatson, G. (2010).  Effect of milk-based carbohydrate-protein supplement timing on the attenuation of exercise-induced muscle damage. Applied Physiology, Nutrition, Metabolism, 35, 270-277.

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7 responses

  1. Costco sells the best little cartons of chocolate milk and they are delicious cold. I just ran out and I am going to get more. Didn’t know you “peed less” drinking choc. milk. I always consumed massive amounts of H2O.

    • Yes, isn’t that interesting?! You “pee less” than drinking the same amount of water because you not only hydrate intercellularly, but inTRAcellularly. It has the right concentration so that your cells can absorb the water instead of your body rushing to push the excess water out through your kidneys.

    • Great question! V8 is decent and does have value!
      The Ups:
      Let’s consider the original old-school V8. For an after workout drink, it doesn’t have that “ideal ratio” as it has 10 grams of carbs and 2 grams of protein, but it has sodium, calcium, and potassium for your electrolytes! The majority of V8 is tomato juice, which is a healthy dose of lycopene (a carotenoid that has been associated with a reduced risk of some cancers) and some other exciting vitamins. The sodium is high, but as a post workout drink for non-hypertensives (people who do not high blood pressure), I wouldn’t worry about it if you only have a can. If you are watching your sodium you could grab the low-sodium version (which appears to have more potassium as well!) (Of course if you are sodium-restricted for a medical reason, don’t have either!)

      The not-so-much:
      That being said, it is unclear about how much of V8 is juices from other veggies. I would consider this mostly reconstituted tomato juice (and less celery, carrots, beets, lettuce, etc.). Which is fine, the availability of lycopene is higher in processed tomatoes! But it is only juice, and only from predominantly one veggie, so it doesn’t take the place of whole veggies, that have fiber, nor does it hit the mark for variety. Also, some people are sodium sensitive (but that’s a blog for another day).

      Overall, great question and good choice! You: A. V8: B. I give it a B+ if you use it as a post-heavy-workout drink!

  2. Pingback: Quickie of the Week Part 2: Calcium and weight loss?! Milk and mucous? What about my Broccoli?! | 411nutrition

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