Post Workout Carbohydrate Sources
By Kyle Hunt
Research in discussion
Effects of ingesting protein with various forms of carbohydrate following resistance-exercise on substrate availability and markers of anabolism, catabolism, and immunity
The ingestion of carbohydrate and protein following resistance training is a general protocol for most athletes interested in optimizing their gains from training. The combination of carbohydrate and protein has been shown to increase insulin levels, optimize glycogen re-synthesis, enhance protein synthesis, and lesson the immunosuppressive effects of intense exercise. There has been a lot of research conducted on the varying recovery properties of different protein and amino acid sources but much less research done on different forms of carbohydrate sources. Theoretically, ingesting a carbohydrate source that has a high glycimic index would offer the greatest increase in insulin levels, glycogen re-synthesis, and protein synthesis. The big question is whether or not the glycimic index (speed of delivery) makes a difference when combined with protein and taken post workout.
The purpose of the study was to determine whether the type of carbohydrate ingested along with protein (whey) following a resistance exercise affects blood glucose availability and insulin levels, markers of anabolism and catabolism, and/or general immune markers.
The research group used forty subjects (19 males 21 females) who had all participated in at least one year of resistance training prior to the experiment. Before the start of the program, one repetition maxes were found for the given exercises in the program along with starting body weight. Before the start of the training sessions the subjects gave “pre-exercise” blood and after completing the given resistance training workout the subjects gave “post-exercise” blood.
Following the post exercise blood sample, the subjects received in a double blind and randomized manner a carbohydrate and protein supplement consisting of 40g whey protein with 120g sucrose, powdered honey or maltodextrin. The remaining group was served as a non supplement control group.
The research group had three major findings after concluding the study. One, ingesting a carbohydrate and protein supplement following resistance training promoted significant increases in insulin level. This was not a major finding as many studies have showed the same thing. Two, there were no significant differences observed among the forms of carbohydrate served on the insulin levels. This suggests that all three carbohydrate sources tested when combined with protein are effective for post workout recovery. Lastly, the group found that glucose was maintained to a greater degree in the subjects ingesting honey as the carbohydrate source. This was an interesting point because honey has the lowest glycimic value of the three carbohydrates tested and symbolized a “mix” carbohydrate source. The honey used in the study was made up of a mixture of fructose, glucose, wheat starch, and maltose. The study also concluded that the differences in post workout supplementation did not significantly affect time course of testosterone, cortisol or general markers of immunity. Like previously mentioned the findings support the growing literature that ingesting post workout carbohydrates combined with protein stimulates insulin levels and anabolic processes. However, the study brings up an interesting point in regards to post workout carbohydrate intake; faster absorption might not be as beneficial as originally imagined.
It has generally been thought that insulin levels increase the greatest amount in conjunction with higher glycimic index carbohydrates. Thus it would provide the greatest benefit to combine protein with the highest possible glycimic index carbohydrate post workout such as dextrose, maltodextrin or like substance to benefit from all of the anabolic processes of insulin. However, the research showed there was little to no difference between carbohydrate sources tested in the study. A possible explanation for this could be the effect of the whey protein supplement on the carbohydrate source. Glycimic Index values are determined fasted and as an isolated food item. When the carbohydrate is combined with the whey protein a whole new cascade physiological response occurs compared to the carbohydrate isolated.
Post workout supplementation protocol is one of the most debated aspects in sports nutrition. In addition, over the last few years a lot of post workout supplements have came onto the scene marketed as recovery formulas with dextrose, waximaize, or maltodextrin as their carbohydrate source. The reasoning behind having those carbohydrate sources is their extremely high glycimic index values. Dextrose, waximaize and maltodextrin all have glycimic values at or above 100.
It is important to consume protein and amino acids post workout because of the powerful stimulation effects on protein synthesis. Insulin is therefore included because insulin has been found to be a potent stimulator of protein synthesis. The research study showed no significant differences on insulin response of the three forms of carbohydrate tested. Also, honey was found to maintain elevated blood glucose levels to a greater degree than either sucrose or maltodextrin. These findings suggest that it might be more beneficial to ingest a mix of high and moderate glycimic carbohydrate sources post workout to promote a sustained elevation in blood glucose. Also, by combining varying carbohydrate sources consisting of a range of GI values it could prevent rebound hypoglycemia that some individuals may encounter when ingesting extremely high GI carbohydrate sources in large amounts.
Personally I feel like the study was very well put together. However, in the future I would be interested to look into the differences between mixed carbohydrate sources and see if there is any benefit to the combination of high GI sources with low GI sources or if a single moderate GI source provided the most benefit. I tend to suggest a mix of a moderate to high GI source combined with a moderate to low GI source post workout. The idea is to create an initial insulin response but one that is able to be sustained over an extended period of time. An exception to that is during extreme fat loss phases where I feel it is more beneficial to control insulin levels throughout the day and just have a moderate to low GI carbohydrate source post workout.
It is a general consensus that combining protein and carbohydrates together post workout significantly increase glucose and insulin responses thus anabolic processes. The findings suggest that each of the three types of carbohydrates tested can be used as an effective carbohydrate source to combine with protein and consume post workout. However, it was found that blood glucose levels could remain elevated if a “mix” carbohydrate source was consumed such as honey.
In a post resistance workout setting there seems to be no added benefit to consume an extremely high GI carb source such as dextrose, waximaize or maltodextrin. In fact, like mentioned I would recommend a mix of a high and moderate glycimic index carbohydrate source to generate an insulin response and maintain it over a greater period of time. The study does not say that having a high GI carbohydrate source such as dextrose, maltodextrin, or waximaize post workout is not effective. It is effective it’s just not any MORE effective than having a moderate carbohydrate source or a mix. I would try a few different protocols and determine what your body responds to best.
Post Workout CHO Intake Q & A
Here are some of the more common questions I get regarding post workout intake.
Q- If you are following a low carbohydrate diet do you still need carbohydrates post workout?
- There this definitely a great deal of benefit to consuming carbohydrates post workout. Like mentioned the ingestion of carbohydrates and protein create a cascade of events including increased protein synthesis, increased glucose and nutrient uptake within the muscle cell and it stems from the insulin response. Typically in a low carbohydrate setting I would recommend partitioning the majority of your carbohydrates to be consumed pre and post workout, post workout being the last place to take carbohydrates from so you can still benefit from the muscle building properties of carbs plus protein post workout. However, if you are following a ketogenic diet where the idea is to keep the body producing ketone bodies the only way to do that is to limit all insulin response therefore no significant carbohydrate can be ingested at one time or at all. In those cases its best to follow the plan and avoid carbohydrates.
Q- Do you have to have a supplement post workout or is whole food alright?
- Whole food is definitely alright. For me personally I am about 50/50 when it comes to supplements vs. whole food post workout. Some days I might have a shake along with some carbs and some days I might just have a meal. It really comes down to personal preference and convenience. There are some benefits from having whey protein post workout but most of the benefits stem from maximizing protein synthesis. Since whey protein is about 10-11% leucine it only takes about 30g to hit the leucine threshold to maximize protein synthesis. To make up for that with a whole food source such as chicken, you just need to slightly increased the serving size in comparison to the whey. A great whole food post workout meal could be 6oz chicken, 8oz sweet potato, a little bit of brown sugar and stevia on the sweet potato and there you go! Solid whole food post workout meal.
Q- How important is it to restore glycogen levels post resistance training workout?
- Well this is a good question. Yes, stored glycogen levels are typically on the low side following a resistance training workout, especially if it was an intense workout. But the benefits of restoring glycogen post workout are a much different need to resistance training than it is to endurance training. Your body has about 400g of glycogen stored in muscle cells and about 100g stored in the liver. It only takes about 60 minutes of moderate (65-70% vo2) exercise to completely burn through stored glycogen. To an endurance athlete it is extremely important to restore the glycogen levels so they can train again. A resistance trainer is looking to restore glycogen for another reason. There is only two ways glucose gets into the muscle cell. One is through muscle contraction and another is through the action of insulin. For this discussion we are going to focus on insulin. Insulin acts on GLUT-4 which transports glucose into the muscle cell from the blood. A resistance trainer is looking to benefit from the increased uptake of nutrients, amino acids and the increased muscle protein synthesis response this creates. This really hits on the overall meaning of this article. Yes, insulin is important for muscle growth and recovery but restoring glycogen is not really the main principle of concern. For muscle growth it is more about taking advantage of the physiological cascade of events insulin creates.
I hope this article helps clear the light on some of the more pressing issues of post workout nutrition intake.
Until next time “One Dream, One Reality”
Muscle Building Tips Part 1: Nutrition
Ok here is something to consider. You’re in the gym for only an hour or so each day, the rest of the day your body depends on nutrition and rest to make progress. The problem is proper nutrition and rest often gets neglected. That’s why I am covering nutrition and rest as the first two parts of my muscle building tips. If you are in the gym struggling to build muscle read on because this is part one of a miniseries on how to get big! Part two is going to be on recovery principles and part three is going to be on training. Enjoy and grow!
Tip # 1 – Eat enough calories
To build muscle it is very important to eat enough calories. It comes down to basic math, calories in versus calories out. If you are trying to build muscle it is important to consume more calories than you burn. It is basically impossible to build new muscle if your body is in a negative calorie state. To make sure you are consuming enough calories determine your Lean Body Mass (body weight lbs – body fat lbs) and multiply by 15-25 calories depending on your metabolism/body type.
Tip # 2 – Frequent Eating
Aim to eat every 2.5-3 hours. This will supply your muscle with a constant supply of nutrients they need to grow. Feeling hungry is a sign your body is going into a catabolic state. Also when your starving you are more likely to eat whatever is in the cupboards regardless if it’s on your diet or not. Remember we are trying to gain muscle not fat!
Tip # 3 – Eat before bed
Before going to bed you want to consume some slow digesting protein along with healthy fat. This is to make sure there is a slow stream of amino acids through the overnight to hold off catabolism. Casein protein is a good option at this time because casein is a slow acting protein found in milk. Milk protein is made up of 80 percent casein and 20 percent whey. Casein coagulates in the stomach causing a slow release of amino acids for an extended period of time. You can buy a casein powder or just have cottage cheese. The protein that makes up cottage cheese is mostly from casein because the whey was drained off in the processing. The addition of fat slows down digestion even more. Add some peanut butter or almonds to your before bed snack to build muscle all night long!
Tip # 4 – Do not be afraid of carbs!
It takes more to build muscle than protein. To build mass you must consume enough carbohydrates to energize and fuel your workouts. Shoot for clean low G.I sources such as oatmeal, sweet potatoes, and brown rice. Consume the bulk of your carbohydrates post workout and at breakfast because that is when your body needs them most.
Tip # 5 – The nutritional F-word
Fat is necessary for building mass. By now most people know that fat is not as bad for you as once thought. But what if I was to say even saturated fat is needed in a mass gaining diet? Well it is true; saturated fat has a place in a muscle building diet. For one saturated fat helps with testosterone production and it also helps protect the joints from the damages of heavy lifting. The only type of fat to avoid is Trans fat. Read the label! Even if it says “trans fat free” if there is “partially hydrogenated oil” trans fat is there. Of course the unsaturated “healthy” fats are needed as well. Make sure to get in monounsaturated fat from almonds, avocados, olive oil and your polyunsaturated fat form flaxseeds, walnuts and fatty fish. Consume anywhere from 20 to 30 percent of your daily calories from fat.
Tip # 6 – Water yourself
I have said this before but I will say it again, your body needs a lot of water to function properly. When you give your body lots of water everything runs smoothly. Water also helps with digestion so drink up!
Tip # 7 – Last but not least! Post workout meal
Ok this topic has generated a lot of discussion over the last decade and I feel there are a lot of myths that need to be mentioned. First off I believe carbs are necessary for proper recovery post workout. Following an intense workout your glycogen levels are low and your muscles are depleted. This is the perfect time for carbohydrate and protein intake. Secondly you want to consume a carbohydrate source that creates a high glycimic load. Notice I did not say anything about glycimic index. I feel too much consideration is given to the glycimic index but not enough to the glycimic load. For bodybuilders glycimic load is more important, it takes into consideration an entire meal rather than a single food. Another important point is the carbohydrate source does not need to be the fastest digested source possible. I would rather take in a source of carbohydrate that offers some nutritional density to it rather than just some dextrose that has no nutritional value what so ever. Another controversial topic is timing of this meal. Some would say immediately post workout, as soon as you put down the last weight start in with your post workout meal. Research shows that the “special window” is actually longer than originally thought. Therefore don’t stress about racing to get your post workout meal in. Actually waiting a little bit might be optimal, this gives your digestive system time to recoup some blood from the working muscle to use for digestion. Lastly I wanted to talk about how to structure your post workout meal to give you the best results. To start off I like to have a fast acting protein source like whey. Whey is perfect for post workout, fast acting, loaded with BCAAs and ect. Secondly I like to add a relatively fast acting carb to my whey shake. My carb of choice is a russet potato. I like russet potatoes post workout because they are loaded with potassium and my body fills up quite well on them. I also use oats with my whey shake post workout. I normally have a complete whole food meal 2 -2.5 hrs after my post workout meal.
Up next Tips on proper recovery for muscle building!
Live it! “one dream. one reality”