Are Post-workout Carbs Necessary?

One question we get asked a lot is whether carbs are absolutely necessary post workout, especially if fat loss is the major goal. The short answer is: no. In fact, in some of my programs you may be cutting out all carbs if you’re in the extreme phase of a diet.

However, you should do yourself a favor by regularly enjoying some post-workout carbs, along with protein, and at least creatine and beta-alanine, for better recovery and muscle growth, without worrying about them interfering with weight loss.

It’s the $64,000 question when you’re replenish muscle glycogen to aid recovery, while trying to cut weight. Here’s the answer…

 

Do your glycogen good

The main reason for consuming carbs after exercise is to replenish the muscle glycogen you burned during the workout. Glycogen is the stored form of glucose in the muscles. It is composed of glucose molecules strung together in long strings, which are broken off from the glycogen chain to create adenosine triphosphate (ATP).

Research on muscle glycogen levels during weight training shows workouts consisting of anywhere from six to 20 sets, and lasting 15–30 minutes, deplete glycogen by 30–40%. Higher volume workouts will deplete it even more.

The best way to replenish glycogen stores post workout is to consume high-glycemic carbs immediately afterwards. Delaying carb consumption by just two hours reduces the glycogen replenishment rate by 50%.

Yet some experts argue none of this matters for most gym-goers because there is minimal evidence suggesting that no matter when you replenish glycogen post workout, it returns to its natural levels after 24 hours anyway. But if you need to replenish them quicker then you need to consume fast-digesting carbs sooner post workout.

Replenishing your muscle glycogen level as soon as possible is vital because it pulls water into your muscle cells, increasing their volume and therefore muscle fiber fullness. And evidence suggests maintaining a post-workout ‘pump’ as long as possible can lead to long-term muscle growth.

 

In debt of insulin

Another benefit of high-glycemic carbs is the insulin spike they deliver. While insulin is considered an anabolic hormone, its role in muscle growth is now much debated.

While it was once thought vital in instigating muscle protein synthesis and decreasing muscle breakdown, some evidence now suggests its role is not so critical. More important appears to be the delivery of enough amino acids, from an adequate amount of protein, to the muscle cells.

Recent research comparing the consumption of just protein post workout to the consumption of protein plus carbs shows that as far as protein synthesis is concerned, the addition of carbs to a protein shake does not boost muscle protein synthesis, or decrease muscle breakdown any greater than with just the protein shake.

More important is leucine, which has been shown to increase insulin levels; not quite as high as when carbs are consumed along with a leucine-rich protein source, but adequate enough to encourage muscle growth.

 

Dealing dextrose

Dextrose, which is basically glucose by another name, is the best source for post workout carbs. Consuming pure dextrose after a workout means the body doesn’t need to digest it and it can be absorbed into the bloodstream almost as quickly as it is ingested. This, in effect, gets a dose of glucose to your spent muscles as quickly as possible. Maltodextrin is another good option because it is a chain of glucose molecules that rapidly breaks apart into glucose molecules within your digestive tract.

A less than ideal post-workout carb source is the sugar fructose (50% of the sugar in most fruits and honey is fructose), which is a low-glycemic carbohydrate. Unfortunately the body can’t directly turn fructose into glucose due to its structure.

So when you consume fructose, it doesn’t get absorbed immediately into the bloodstream like glucose/dextrose. Instead, the majority of it must travel to the liver where it can be converted and stored as glycogen to be released into the bloodstream as and when required.

Fructose’s failings are the reason I recommend opting for gummy bears instead of fruit. Gummy bears, such as the Haribo brand, use dextrose and corn syrup as sweeteners, and so will get to the vital areas of your muscles a lot quicker to aid with synthesis.

 

Why risk it?

So why would you risk not consuming carbs after a workout only to eat them hours later? It would seem idiotic given we know that consuming high-glycemic carbs right after exercise is the optimal way to restock your spent muscle glycogen.

Many people worry fast-acting carbs will make them fat. Yet it’s the one time of day you are almost guaranteed that carbs won’t be converted into body fat. And if you are dieting I’d recommend you cut the carbs from other meals before cutting the post-workout ones. You could also be be worried about post-workout carbs because some expert claimed eating them right after exercise can lower growth hormone (GH) and testosterone levels, and that a better option is to wait a few hours.

Personally, I think this advice is flawed, because growth hormone and testosterone levels peak during a workout and plummet straight afterwards whether you eat anything or not. So put all your worries about eating carbs post workout away and worry more about doing everything possible to optimize your recovery. This includes a protein powder blend of at least whey and casein protein along with 20–40g high-glycemic carbs. I guarantee the results will speak for themselves.

 

Find nutritional advice and more in every issue of TRAIN magazine. 

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