Carbohydrates after training - positives and negatives

Are post-workout carbohydrates necessary to achieve optimal muscle growth? This is a question we face every day, and maybe this article will give you the answer you've been longing for.

Do you need carbohydrates for maximum muscle growth after training?

The role of carbohydrates in training, health, and longevity is a hot topic in gyms and labs alike. Many bodybuilders drastically limit carbohydrates in training. For others, this in turn causes anxiety, due to fear of muscle loss. To be clear - any dietary restriction will cause the loss of hard-earned muscle. However, low carbohydrate intake does not necessarily mean low energy intake. It can be compensated for with fat and protein.

Many studies have confirmed the positive effects of a low-carbohydrate diet on indicators of heart disease and metabolic syndrome. Dr. Jeff Volek and his lab at the University of Connecticut have published many articles on the positives ofa ketogenic diet, including the positives for performance athletes.1

Such a diet usually involves consuming less than 50 grams of carbohydrates per day.

Dr. Volek has shown better maintenance of lean muscle mass and improvements in fat metabolism, compared to low-fat diets.2 He also showed that adaptation to ketosis changed energy handling during endurance training so that more fat was burned.

Once your body (i.e., brain and muscles) adapts to using fat as fuel, it reduces the risk of that jolting feeling that occurs when glycogen stores are depleted by intense training. Thus, even endurance athletes could benefit from a low-carbohydrate diet.

However, there is always the argument that carbohydrates are needed for muscle maintenance and recovery after training. We often hear from various experts that, "A starving body needs to be supplied with fast carbohydrates immediately after training to kick-start insulin and muscle growth." However, does the scientific material really support this view?

Glycogen stores are depleted after training

Let's look at the basics. Research has shown that maximum protein synthesis of the amino acid leucine is achieved by insulin.3 However, leucine alone can increase insulin concentrations by 3 to 4 times compared to normal.4 So if you take a whey protein that is rich in leucine after a workout, do you even need more carbohydrates?

The conjecture about the need for carbohydrates post-workout probably started with research into replacing depleted glycogen after training. After a long endurance workout such as running, your glycogen stores (stored glucose) can be greatly depleted. Studies show that consuming carbohydrates after such training improves glycogen storage recovery.5

In contrast, intense training units usually do not cause such a significant glycogen depletion - 40% maximum. If you don't have another workout in the next eight hours, your glycogen stores are easily restored from regular meals between the two workouts.

Goals anddiet

This brings us to the next question. What are your training goals? Do you want to get big and strong (outside of competition)? Or do you want to be sculpted (pre-competition period)?

If you want to build maximum muscle, you need calories. Carbs, especially fast ones, cause insulin levels to spike. When insulin rises, glucose and amino acids are quickly transported into muscle cells, and the muscle-building machinery kicks into high gear.

However, the storage machinery also kicks in, and any energy not used for muscle building will be stored as fat. The combination of protein, carbohydrates, and creatine before and after training has been shown to have positive effects on muscle building, that is, compared to other times of the day.6 If your goal is just volume, then what are you waiting for with post-workout meals? Eat to grow.

For weight loss, then, you need to keep insulin and carbohydrate levels low in circulation. If your insulin is high and you have enough glycogen in your muscles, several things will happen. Insulin first shuts down the hormones that mobilize fat. Then it kick-starts the enzymes that store them, and finally your muscles learn to use insulin as fuel whenever it's available. So you'll get most of your energy from glycogen. If you want to burn fat, you have to force your muscles to need it. This requires emptying your glycogen stores.

This brings us back to the question of whether we need glucose and insulin to perform in the gym and hold muscle while dieting. It is true that training hard can reduce your performance in the next workout you perform on the same day.7

However, studies show that on a low-carbohydrate diet, muscles can become accustomed to using intramuscular triglycerides as fuel for training.8

Studies also show that glycogen depletion can have a pretty small effect on performance in the gym.9 If your goal is strength and muscle building, you're fighting opposing forces, and you'll probably need to reevaluate your goals.

If you love your sugars, one study replaced dietary fat with protein and kept carbohydrate intake the same. This all took place during a caloric deficit, and the trained individuals maintained most of their muscle this way.10 The question is whether the muscle was maintained by maintaining carbohydrates or adding protein.

One would almost say that glucose and insulin prevent muscle breakdown during training. A study by Børsheim et al. showed that 100 grams of carbohydrate after training increased insulin levels and reduced muscle degradation.11 However, there are studies that attribute the same ability to adequate amino acid intake.12

Anabolic supercompensation can occur with adequate post-training intake of carbohydrate, protein , and leucine even during highly catabolic fasted training.13 But is protein or carbohydrate playing a critical role here?

Protein or carbohydrate?

Studies that have evaluated the posttraining anabolic response to a combination of protein and carbohydrate have not demonstrated its superiority over adequate protein intake alone.14

When high-quality protein such as whey is consumed, muscle proteosynthesis can be maximized without additional carbohydrates. Only a slight increase in insulin levels is needed to achieve maximum anabolism, and amino acids can do this without the presence of carbohydrates.14

It has already been suggested that the ability of a protein to maximize proteosynthesis is determined solely by its leucine content.15 HMB, the breakdown product of leucine, can also inhibit muscle catabolism in the absence of energy.

One study on cornstarch and maltodextrin is worth mentioning here. Roberts and colleagues at the University of Oklahoma examined the consumption of cornstarch and maltodextrin before intense training.16 Their findings were quite interesting. Maltodextrin spiked blood glucose and insulin more than cornstarch. Corn starch may be better for endurance training, but not for acute insulin response and anabolism.

The superiority of protein to carbohydrate is further supported by a study comparing soy and casein. When a supplement containing soy and rapidly digestible maltodextrin was compared to a supplement containing casein and the same amount of slowly digestible lactose, the casein group still showed a higher protein synthesis value. Here again, the elevated post-training insulin levels were downstream of leucine availability.15,18

Thus, to achieve insulin benefit beyond that provided by protein alone requires doses that humans normally receive only under medical supervision (as some bodybuilders have already discovered).19

Factors toconsider

So let's draw some conclusions. Whether you should consume carbohydrates at all after training depends on many factors:

1. your main goal:

If you want volume, regardless of fat burning, go all in. After your workout, have carbs, protein and creatine. You have increased blood flow as well as glucose and nutrient transport. Feed your muscles immediately after your workout.

However, if you are in a glycogen-restricted state, due to weight loss, why spike your insulin levels after your workout? Have only protein after your workout, which will only raise your insulin slightly, and let your fat burning run unhindered. If you want to gain muscle without fat, get as many calories from whey protein as you can handle.17

If you want to train hard twice a day and have less than eight hours between workouts, have a post-workout carbohydrate to replenish depleted glycogen stores. That is, if you want to do a good job in your second workout.

2. Your total nutrient ratio for the day:

If you're keeping carbs low due to ketosis, you want to have them evenly distributed into your daily dose of vegetables. Stuffing yourself with carbs post-workout won't be feasible in this case. Studies show that you don't even need added carbs to maximize post-workout protein synthesis.

If you normally eat carbs in your meals, plan to have one immediately after your workout. Studies are quite divided on the timing of post-workout meals, showing anywhere from no effect to a positive effect. However, none show a negative effect of eating a meal with protein and carbs directly after training. So you can't lose anything.

Sources:
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2. Volek JS, et al. Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Lipids. 2009 Apr;44(4):297-309.
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