“What’s the best thing to eat straight after training?” wrote one Muscle Evo reader.
“I’ve heard that I need fast-digesting carbs to replenish glycogen, spike insulin and gain muscle. But I’ve also read that taking in carbohydrate after exercise will stop me burning fat? Who’s right?”
The idea behind taking a large amount of fast-digesting carbohydrate after a workout is that it accelerates the rate at which glycogen – the name given to carbohydrate stored in your body – is replenished.
This in turn is supposed to help you recover and grow more quickly.
It’s true that muscle glycogen is synthesized more rapidly if you take in some carbs immediately after a workout rather than several hours later.
In fact, delaying the consumption of post-workout carbs for just two hours has been shown to slow the rate of muscle glycogen resynthesis by as much as 50% .
But as long as you’re getting enough carbohydrate in your diet, glycogen levels will return to normal after a day or two, regardless of when that carbohydrate is consumed [1, 2] .
From a research review on the subject of nutrient timing and muscle growth :
Without question, expediting glycogen resynthesis is important for a narrow subset of endurance sports where the duration between glycogen-depleting events is limited to less than approximately 8 hours.
Similar benefits could potentially be obtained by those who perform two-a-day split resistance training bouts (i.e. morning and evening) provided the same muscles will be worked during the respective sessions.
However, for goals that are not specifically focused on the performance of multiple exercise bouts in the same day, the urgency of glycogen resynthesis is greatly diminished.
In other words, while the speed of glycogen restoration is important for some people in certain circumstances, for most of us it isn’t.
The idea that you need carbohydrate immediately after a workout to “spike” insulin levels and gain muscle is also a myth.
For one, many protein-rich foods trigger a rise in insulin in the same way that carbohydrates do.
Whey protein, for example, has a much bigger impact on insulin levels than even pure glucose. The rise in insulin from protein alone is enough to inhibit the increased rate of muscle protein breakdown that normally happens after training with weights.
In one study, taking 50 grams of carbohydrate with 25 grams of whey protein after exercise failed to stimulate muscle protein synthesis or inhibit protein breakdown to a greater extent than 25 grams of protein alone .
Carbs can inhibit protein breakdown if you’re taking only carbohydrate and nothing else, or when those carbs are co-ingested with a very small amount (less than 10 grams) of protein.
But if you’re taking in a reasonable amount of protein after training, the addition of carbohydrate isn’t going to help you gain muscle any faster.
Dig through the research, and you’ll find very little evidence to show that the addition of post-workout carbs to a protein shake has any additional muscle-building benefits compared to the protein shake alone .
What about fat loss?
You may have heard that taking on board fast-acting carbs immediately after exercise will sabotage your attempts to get lean.
The research on the subject is a bit of a mixed bag. Some studies show that a carbohydrate-rich meal after exercise puts the brakes on fat oxidation, while others show that it has no effect.
One trial, which looked at fat metabolism for three hours after a post-workout meal or plain water, shows little difference in the number of fat calories burned .
A study published in the British Journal of Nutrition shows that fat oxidation remains high even when a high carbohydrate meal (400 grams of pasta) is eaten after exercise .
On the flip side, Colorado State University researchers found a marked drop in fat oxidation when a carbohydrate-rich mixed meal was consumed immediately after exercise . A Canadian team also found that replacing the calories burned during exercise with a post-exercise milk shake limits the normal rise in fat metabolism that occurs after a workout .
However, all four of these studies have limited practical application, and here’s why.
If you really wanted to establish the effect of post-exercise carbohydrate on fat loss, you’d need to look at changes in body composition over a period of 2-3 months. Measuring fat metabolism during a narrow window of time immediately after exercise gives you a very limited picture about what’s going on.
To lose fat, all you need is an energy deficit. As long as a post-workout meal/shake doesn’t reduce or eliminate that deficit, it’s not going to slow your rate of fat loss.
In summary, there’s nothing wrong with taking in carbohydrate after you train.
It’s not going to stop you losing fat.
But nor will it make a great deal of difference to the speed at which you gain muscle, and is not as vital as was once believed.
SEE ALSO: THE FLAT BELLY CHEAT SHEET
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It's a “cut the waffle and just tell me what to do” PDF, written in plain English, that tells you exactly how to get rid of belly fat. To download a free copy please click or tap here.
ABOUT CHRISTIAN FINNChristian Finn holds a master's degree with distinction in exercise science, is a former personal trainer and has been featured on BBC TV and radio, as well as in Men's Health, Men's Fitness, Fit Pro, Zest, and Perfect Body magazine.
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