Research Review

Bird SP et al. Liquid carbohydrate/essential amino acid ingestion during a short-term bout of resistance exercise suppresses myofibrillar protein degradation. Metabolism. (2006) 55:570-7.

A number of physiological events including the level of contractile activity, nutrient status, and hormonal action influence the magnitude of exercise-induced skeletal muscle growth. However, it is not the independent action of a single mechanism, but the complex interaction between events that enhance the long-term adaptations to resistance training. The purpose of the present investigation was to examine the influence of liquid carbohydrate (CHO) and essential amino acid (EAA) ingestion during resistance exercise and modification of the immediate hormonal response on myofibrillar protein degradation as assessed by 3-methylhistidine (3-MH) excretion. After a 4-hour fast, 32 untrained young men (18-29 years) performed a single bout of resistance exercise (complete body; 3 setsx10 repetitions at 75% of 1-repetition maximum; 1-minute rest between sets), during which they consumed a 6% CHO (n=8) solution, a 6-g EAA (n=8) mixture, a combined CHO+EAA (n=8) supplement, or placebo (PLA; n=8) beverage. Resistance exercise performed in conjunction with CHO and CHO+EAA ingestion resulted in significantly elevated (P<.001) glucose and insulin concentrations above baseline, whereas EAA ingestion only increased the postexercise insulin response (P<.05). Time matched at 60 minutes, the PLA group exhibited a peak cortisol increase of 105% (P<.001) with no significant change in glucose or insulin concentrations. Conversely, the CHO and CHO+EAA groups displayed a decrease in cortisol levels of 11% and 7%, respectively. Coinciding with these hormonal response patterns were significant differences in myofibrillar protein degradation. Ingestion of the EAA and CHO treatments attenuated 3-MH excretion 48 hours after the exercise bout. Moreover, this response was synergistically potentiated when the 2 treatments were combined, with CHO+EAA ingestion resulting in a 27% reduction (P<.01) in 3-MH excretion. In contrast, the PLA group displayed a 56% increase (P<.01) in 3-MH excretion. These data demonstrate that not only does CHO and EAA ingestion during the exercise bout suppress exercise-induced cortisol release; the stimulatory effect of resistance exercise on myofibrillar protein degradation can be attenuated, most dramatically when the treatments are combined (CHO+EAA). Through an "anticatabolic effect," this altered balance may better favor the conservation of myofibrillar protein.

My comments: This is one of those studies that kind of has an "Well, duh" feel to it. Subjects were given either a placebo, a 6% carb solution (think Gatorade), 6 grams of essential amino acids (EAA), or a combined carb/EAA drink during resistance training. This was done after a 4 hour fast (see comments below); various hormonal and other parameters were followed over the next 48 hours including a measurement of 3-methylhistidine excretion, a measure of protein breakdown. Both the carb and carb/EAA group showed a decrease in cortisol levels while the placebo group showed a slight increase. The carb/EAA group also showed an increase in insulin and glucose levels during the workout. At the 48 hour mark, the carb/EAA group showed significantly lower 3-MH excretion compared to the placebo group.

Fundamentally, these results aren't that terribly surprising, given that insulin tends to drop during activity, with an increase in cortisol, consuming carbs during a workout would be expected to prevent these hormonal changes. With the increasing amount of data indicating a role of the EAA in stimulating protein synthesis before and after training, it makes some sense that consuming aminos during a weight training workout would also have a beneficial effect.

About the only parameter of this study that gives me pause is the 4 hour fast prior to the workout. Clearly going into a workout with that long of a time from your last meal changes things relative to say, having eaten 1-2 hours prior to your workout. A meal eaten that close to workout would still be releasing nutrients into the bloodstream and pre- and during-workout nutrition might have less of an impact.

However, it's simple enough to replicate the above study with something as easy as Gatorade (30-60 grams carbs) and 12-15 grams of whey protein (which will provide 6-8 grams of EAA) consumed every hour during training.

Feature Article:

Where is the Bodyfat Part 2

In Part 1, of this article (available in the archives), I covered essential bodyfat and brown adipose tissue; in part 2 I want to cover visceral fat, subcutaneous fat and stubborn bodyfat.

The third type of fat: Visceral fat

Of all the types of fat in the body, visceral fat is probably the one that has gotten the most interest, especially in terms of its effects on health. But let's back up a step and look at what visceral fat actually is first. Visceral fat is found around your internal organs and can be thought of as gut fat. But it's not the fat that you can see on top of your gut ; it's actually underneath your abdominal muscles surrounding your organs.

People who carry a lot of visceral fat are referred to as having central obesity and their tummy pooches out quite a bit from their body. You can go to any mall food court if you want to see examples of this. While this typically happens in males, it can also happen in females under certain conditions, mainly in extreme obesity and after menopause (women who suffer from PCOS also have problems with central obesity).

Although carrying excess fat generally increases health risks, some research suggests that visceral fat is even worse in this regards. At the very least, carrying around a lot of visceral fat is associated with insulin resistance (meaning that insulin can't do its job well), high blood lipids and other risks. This is on top of making your stomach pooch out a lot further than it should. Otherwise lean bodybuilders frequently have a good bit of visceral fat (usually when they have been using a lot of steroids, although this may be due to actual organ growth) which makes them look pregnant, even when their abdominal muscles are clearly visible.

Visceral fat is different than subcutaneous fat (discussed next) in many ways, which is why we're discussing it separately. The biggest difference is that visceral fat is more metabolically active than subcutaneous fat. Meaning that it responds more effectively to fat mobilizing/burning stimuli than other types of fats. It's also less affected by insulin, which tends to shut down fat burning. Visceral fat also has better blood flow compared to other bodyfat, meaning it's easier to get the fat out of the fat cell. All of this adds up to a type of bodyfat that is mobilized more easily than the others.

Visceral fat also appears to undergo something called apoptosis (which just means cell death) more readily than other types of fat. There is also some research showing that visceral fat responds differently to diet and exercise than other types of fat. It appears that aerobic exercise gets rid of visceral fat more effectively than just reducing calories, probably because of the hormonal response involved: aerobics raises catecholamine levels while diets tend to reduce them, and visceral fat is very responsive to catecholamines.

From a body recomposition standpoint, the presence of visceral fat goes a lot further than just making your stomach stick out. Because of the link with insulin resistance, visceral fat makes it more likely that you'll get fat when you're overeating (i.e. trying to gain weight/muscle). So losing visceral fat, especially prior to trying to gain weight, should help to decrease fat gain. In addition to making you a whole lot healthier and giving you a flatter stomach to boot.

Despite all the problems it causes, there is one potentially 'nice' thing about visceral fat: because of its higher metabolic activity and sensitivity to fat burning stimuli, it goes away faster than other types of bodyfat. While this doesn't necessarily make you look visibly better, it's still a good thing. Once visceral fat is gone, your body will be more likely to draw on fatty acids from other places, in this case subcutaneous fat which what most body recompositionists want to get rid of.

The fourth type of fat: Subcutaneous fat

Subcutaneous (sub-q for short) just means 'under the skin' which is where this fat is found. This is the type of fat that most body recompositionists want to be rid of. Preferably yesterday if it's at all possible. When I refer to 'bodyfat', I mean sub-q bodyfat (if I'm talking about visceral bodyfat, I'll say visceral fat) since it's the main type of bodyfat that we're worried about and can affect with diet, training, supplements, or drugs.

Of your total bodyfat (including all of the above 'types' of fat), this type of fat is the most prominent. Anywhere from 40% to 60% of your total bodyfat is found under the skin, which is what allows you to estimate bodyfat percentage with methods such as skinfolds.

As you're probably well aware, people differ quite a bit in how their fat is distributed. Typically, on top of their greater amounts of visceral fat, males carry more of their fat on their midsection and upper back, with much less on their hips and glutes. It's not uncommon to find men who have an extreme amount of bodyfat on their abdominal area while still having very lean legs. This is sometimes called an android bodyfat deposition pattern. It's also described as having an apple shape.

Women, in contrast, typically carry more fat on their hips and thighs with less on their abs. Breast size can vary quite a bit but is another place where women store bodyfat. It's not uncommon for women to be extremely lean in their upper bodies (frequently having visible abdominals) while having fairly fat hips and thighs. This is frequently called a gynoid bodyfat pattern. Others describe it as having a pear shape.

There are, of course exceptions. Little boys and girls display similar bodyfat patterns before puberty, and women who go through menopause without going on hormone replacement therapy can switch to a more male-like bodyfat pattern (including gaining visceral fat). As well, many men will display more gynoid (or female bodyfat patterning) and women can display more android bodyfat patterning (on top of having central obesity). You'll find out what determines bodyfat patterning in the next chapter.

Now, it turns out that even sub-q fat isn't all the same. Hip and thigh fat is metabolically different than abdominal fat, and there may be differences between different 'parts' of abdominal fat. Researchers have identified a superficial and deep abdominal fat which are metabolically distinct and even upper and lower superficial abdominal fat is different than upper superficial fat. Hip and thigh fat is very sensitive to insulin (which stores fat and prevents breakdown) but not very sensitive to the catecholamines (which mobilize fat). Quite in fact, it is the hardest fat to get rid of. My next book project with stubborn bodyfat nad how to get rid of it. Deep abdominal fat is a lot like visceral fat: resistant to insulin and sensitive to the catecholamines. The superficial ab fat is somewhere in the middle between visceral/deep ab fat and thigh fat: it's moderately sensitive to insulin and moderately sensitive to the catecholamines.

The fifth type of fat: Stubborn fat

Now, although most researchers would be apoplectic (what a great word) at what I'm going go say next, I'm going to differentiate subcutaneous bodyfat into two different types: regular fat and stubborn fat. You can probably guess what those mean. Regular fat is the stuff that comes off fairly easily. Just adjust diet and exercise a bit and it comes off without too much trouble.

Stubborn fat is the other kind, the fat that just doesn't seem to want to come off without a nearly superhuman effort. Even then it doesn't always come off. There are a number of physiological reasons that this is the case, that you'll learn about very shortly. The severe muscle loss that frequently occurs in natural bodybuilders usually occurs when they are trying to chase down the last of the stubborn fat. Basically, when your body can't get fat to burn, but needs energy because you're cutting calories, it starts going after muscle at a quicker rate.

In general, fat will come off the body from least to most stubborn. This means that visceral fat, if present, comes off first. Since most women (unless they are very fat, have PCOS, or are post-menopausal) don't have much visceral fat, this isn't much of an issue. The presence of visceral fat is part of why men lose fat faster on a diet/exercise program than women: the visceral fat is so easy to get rid of and there's usually plenty of it. Next up would be deep abdominal fat. After that would be superficial abdominal fat. The last to come off (if it comes off at all) is hip and thigh fat.

Now, since men don't typically carry a lot of hip and thigh fat, ab fat (superficial ab fat) is their stubborn fat. It's not uncommon to see men who are lean everywhere on their body but still have love handles. For women, unless they have atypical fat patterns, hip and thigh fat is always the last to come off. As I've mentioned, women with a cut/lean/emaciated upper body and fat hips and thighs is not an uncommon sight. As Dan Duchaine pointed out in "Bodyopus", it can be so extreme in women that it looks like two different bodies were attached at the waist.

There are a lot of reasons that stubborn fat acts the way it acts: blood flow, differences in the numbers of certain types of receptors and overall lipolytic activity, even differences in the types of fatty acids which are stored there. My next book project, after I put the protein thing to bed will address the issue of stubborn bodyfat, as well as offering a number of solutions to the problem.

And, no, I can't explain why women put fat on the backs of their arms. I've thought about it for years and simply can't begin to come up with a reason women put fat there. I'm not sure anybody can but if you do, please mail me.

Questions and Answers

Q: What's the best way to teach/learn a new exercise?

A: I'd say the most common recommendation for teaching someone a new exercise, or learning a movement is to use light weights and high repetitions (usually 10-12 or even higher). However, this approach has a problem, especially with relative beginners. That problem is that, with such high repetitions, even with light weights, fatigue starts to set in and form/technique deteriorates.

A key aspect of motor learning, especially for new skills is that they need to be done fresh and in an unfatigued state. Forcing someone to do 15 repetitions of a squat or deadlift tends to make their form fall apart as they get fatigued.

An alternative approach is to do multiple low-repetition sets (5 repetitions is a good number) but still with a fairly light weight. Done for 5 sets, you can get 25 quality repetitions without generating the kind of fatigue that you'd get with multiple set of 12 or 15 repetitions. Typically you might start with the bar (or lighter for some movements) for 5 repetitions.

If that was done correctly, you would add a small amount of weight (this might be 5 lbs for a bench press and 5-10 lbs or more for a squat or deadlift) and perform 5 more repetitions. If those were still good and not too challenging, more weight would be added. If the weight started to get challenging, or form started to break down, you'd either stick with that same weight for the workout or possibly drop back down. So a beginner being taught a squat might go

barX5, 55X5, 65X5, 75X5 (let's say that this looks challenging), 75X5

in their first workout. At the next workout, you might start them at 55 or 65 and pyramid up again. They might go 55, 65, 75, 85, 85 at the next workout. Then 65, 75, 85, 95, 100 at the next. You get the idea.

This way, they'd get a lot of solid form practice. Additionally, many trainees find that movements are a little bit easier to perform with some weight on the bar; it can actually be more difficult if the weight is too light. Adding some weight to the bar lets you find a weight that's challenging enough to let them feel what's going on without pushing them too hard and causing form to suffer.

The danger of low using low repetitions for learning a new movement is the impatience of most trainees, especially males. With only 5 repetition sets, most trainees will tend to want to increase their work weights too quickly and their form will go down the toilet. With a coach watching over them and deciding on weights, this is less of a problem. Left to their own devices, most trainees (again, males moreso than females) will try to add too much weight to the bar and get themselves into trouble.

I should note that this approach is described thoroughly in the excellent book "Starting Strength" by Mark Rippetoe and Lon Kilgore. I cannot highly enough recommend this book to any trainee or coach.

The only other aspect of motor learning I'd like to mention is that learning new movements will occur faster when they are trained more frequently. This is a big part of why I don't like split routines for beginners, they don't get as much practice with the movements as if they trained full body every workout. I like to see new movements trained a minimum of twice/week and three times/week might be better. After 4-6 weeks, the frequency of training can be reduced (if desired) as the intensity increases.

Q: Hi. I really enjoy your weekly newsletter. My question is about loose skin after weight loss. Some "experts" say it's a matter of body recomposition that you only have loose skin if you are the losing lean muscle that you want to keep. What's your take on this?

A: It seems like whether or not people end up with loose skin when they lose weight is fairly genetic; some get it and some don't. It seems that if you're younger (and skin is more pliable/flexible), it tends to bounce back a little more easily but older folks tend not to. Degree of fatness and how rapidly the weight comes off might also have an impact. There doesn't seem to be any fix to it (short of surgery) or any way to know if you will or won't get it.

Q: Please tell us the pros and con's of so-called "fat burning" classes that use multiple repetitions of fairly light weights, some body combat moves, lunges and squats etc. involving 100's of reps in an hour.

A: To be honest, I'm no huge fan of these types of classes. The main reasons (and I'm thinking specifically of things like Bodypump) is that the form you see people using tends to be atrocious. When you give people even medium heavy weights and have them try to lift along with high tempo music, form goes out the window. I don't like seeing that.

Beyond that one issue, these types of classes probably burn a decent number of calories and can deplete muscle glycogen (which tends to enhance full body fat burning) which certainly contribute to fat loss. For a lot of people, the structure of classes (having a large group of like minded supportive people) tends to be motivating and improve adherence. I'm a big fan of anything that gets people coming and staying at the gym.

As a random tangent, I should add that people tend to vastly overestimate how many calories they will burn in a typical aerobics class and this can lead them to rationalize that 'burger and shake that they've earned', offsetting any benefit of the classes. The same is true for most aerobic exercise, though.