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Written by Victor R. Prisk, M.D.
13 November 2017

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Carb-Loading Supplements

Do They Increase Body Fat & Sabotage Your Six Pack?

 

 

Ever go to the gym and see those guys carrying around big jugs of fruit-colored water? It seems there is a belief that we must have plenty of carbs to fuel our training. True, our muscles use glucose from carbohydrate to fuel strength training— but is excessive use of carb-loading supplements leading to body fat retention and defeating our desire to have a six-pack?

 

The role of carbohydrates in sports training, health and longevity is a hot topic of debate in gyms, clinics and laboratories. Physique athletes often utilize very low-carbohydrate diets to get ripped for competition. These diets often provoke anxiety over the idea that this will result in loss of hard-earned muscle. To their dismay, they must realize that any significant restriction of caloric intake can result in the loss of hard-earned muscle. However, low carbohydrate does not necessarily mean low caloric intake. Fat and especially protein can make up for the lack of carbohydrate that would otherwise result in muscle loss.

 

It is certainly true that low-carbohydrate dieting can affect our performance in the gym. Performance that suffers could lead to a lack of stimulus to grow muscle. Weight training to build muscle has completely different energetics than running a marathon. Since we all have massive stores of calories as fat, it is best to maximize the use of fat as fuel when performing a task like long-distance running. Training in a relatively carb-deficient state can help one’s body learn to become “fat adapted” for an endurance challenge. The relatively smaller glycogen stores that fuel resistance exercise need to be restored more deliberately, or performance suffers. Science shows that performance suffers in lower carbohydrate dieting.1

 

It is pretty clear that low-carbohydrate dieting, where healthy fats and higher protein intakes are maintained to limit extreme caloric restriction, is very effective at maintaining lean muscle mass.2,3,4 Studies suggest that despite acute reductions in performance, the lower carbohydrate, high-protein diets are most effective in helping you get lean and maintain muscle.5 As we will further discuss, the carbohydrate intake is not essential to maintaining muscle, just performance.

 

Carb Intake, Performance and Belly Fat: a Fine Balance

The more difficult question becomes, when we are not dieting to lose fat, how much carbohydrate do we need to build as much muscle as possible without getting too fat? You could just carb-load every day, but your body will just store the extra calories as fat. All carbs are absorbed as glucose into your blood, which causes the release of insulin from the pancreas. Glucose is toxic to your blood vessels, causing “caramelizing” of the proteins lining their walls. This leads to inflammation and damage to blood vessels and other tissues that also become caramelized (i.e., tendons, nerves, etc.). Insulin release pushes glucose out of your blood vessels and into the liver, muscle and fat as quickly as possible, while turning on fat-storage enzymes. The more glucose that is present, the more fat is made.

 

It has been suggested that strength athletes need anywhere between four to seven grams per kilogram of bodyweight of carbohydrates for maximal strength-training performance.6 Of course, this is a huge variation, and is dependent on the individual and their stage or intensity of training. If you lean toward seven grams per kilogram, you may find that you gain more fat than you’d like, while four grams per kilogram may limit your gains and/or performance. You will have to figure out this balance for yourself.

 

One thing that seems clear is that there is a fine balance that most certainly deserves avoidance of any all-encompassing statement that says, “You should do this…” However, Antonio and colleagues have shown that one can overindulge in extra whey protein without concerns over generating more belly fat.7 In their research, they found that one can maintain a lean physique without significant addition of body fat, even with more than doubling their protein intake.

 

It is often said that glucose and insulin prevent the breakdown of muscle during intense training. One study by Børsheim et al. did demonstrate that 100 grams of carbohydrate, post workout, causes increases in insulin and reductions in muscle degradation.8 However, studies also demonstrate that adequate consumption of essential amino acids after training causes an increase in insulin that can also limit protein degradation.9 Even in the highly catabolic, fasted training state, anabolic supercompensation can occur with adequate post-exercise carbohydrate, protein and leucine.10 But is it the carbohydrate or the protein that is most important?

 

A combined protein and carbohydrate supplement has failed to show benefit over adequate protein alone.11 When high-quality protein like whey hydrolysate is consumed, muscle protein synthesis can be maximized without additional carbohydrate. Only small elevations in circulating insulin are required to maximize muscle anabolism, and amino acids can stimulate this level of insulin release without carbohydrate present.11 It has been suggested that the leucine content of a protein can determine its ability to maximally stimulate muscle protein synthesis.12

 

Taking in Carbs to Restore Muscle Glycogen

As mentioned earlier, studies also show that carbs may be required on days where you have twice-per-day training sessions. It is thought that carbs after the first workout will restore muscle glycogen for subsequent bouts. The assertion that you need post-workout carbs likely started with literature looking into glycogen repletion after endurance exercise. After a long endurance training session, such as a long run, your glycogen stores can be significantly depleted. Studies demonstrate that consumption of carbohydrate immediately after such a training session improves restoration of muscle glycogen stores.13

 

Conversely, high-intensity resistance training bouts typically don’t cause such significant reductions in muscle glycogen— 40 percent at most. Unless you’re training again in under eight hours, that glycogen content of your muscle will be restored easily from subsequent meals before your next training bout. Further research also suggests that consuming up to eight grams of glutamine can help restore muscle glycogen just as well as a glucose solution.14 Combining the glutamine with the glucose solution promoted storage outside of skeletal muscle like in the liver. So, do we really need extraordinary amounts of carbs to restore muscle glycogen for performance in the gym?

 

Recent studies suggest that training in a low-carb state for high-intensity interval training can improve performance when carbs are added later.17 If your first training session in a day depletes your muscle glycogen and you train in a depleted state for the second session, is it possible that the second session will create more adaptations to the training session? The science suggests that adaptations to the low-carb state help you to perform better in a carb-loaded state. By that thinking, should we be strategically limiting carbs in different training scenarios? Unfortunately, this data didn’t examine maintenance of muscle mass or burning of fat in the long term.

 

In summary, consuming excessive amounts of carbohydrate, especially before training, limits your body’s ability to mobilize fat as fuel and increases storage of the added calories as fat. Excessive carbohydrate intake may even limit your body’s ability to adapt to limited fuel sources. I propose that training without pre-workout carbs will help you mobilize fat and create more muscle machinery for functioning during a pre-contest, carb-restricted diet. I would recommend that you increase your protein intake through supplements like leucine-rich whey isolates in order to avoid fat storage and maximize muscle protein synthesis. Consume complex carbohydrates evenly spaced throughout your day to maintain calories, but avoid excess if you want to avoid a big belly.

 

Dr. Victor Prisk is a board certified orthopaedic surgeon and IFBB professional bodybuilder in Pittsburgh, PA. Dr. Prisk is an active member of the GNC Medical Advisory Board and creator of the “G.A.I.N. Plan.” He is an NCAA All-American gymnast, champion swing dancer and NPC Welterweight National Champion.

 

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