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Appetite For Construction
Oct 26 2001

By Dr. John M Berardi, Ph.D.
First published at www.t-mag.com.

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One Cow, Two Servings

Q: Is there any reason why I can't just eat one or two huge protein meals per day rather than eating five or six small ones? I mean, is there some sort of storage spot in the body for this protein?

A: Simply put, eating one or two huge protein meals per day is a bad idea for weight trainers. First of all, there's a limit to how much protein can be digested and absorbed in the body, although no one has conclusively shown how much protein this is. But even when someone comes out with a number, it won't be applicable to everyone. This is because different individuals will be able to tolerate different protein loads based on body size and habitual level of protein intake. In other words, if you normally consume a high protein diet, then you'll probably be able to digest more protein than someone who eats a low protein diet.

Since we don't know what the upper limit is, and we do know that there's got to be an upper limit to how much protein can be digested in one sitting, we have to guess. Although I can't guess exactly how much this might be, I think it's safe to assume that if you're a 200-pound weightlifter trying to eat only two meals to get a protein intake of one gram per pound of bodyweight, you won't be fully digesting 100 grams of protein in one sitting.

Even if this protein was fully absorbed, there's no storage depot in the body for the absorbed amino acids like there is for carbohydrate (the liver and skeletal muscle) and for fat (adipose tissue and skeletal muscle). Excess amino acids that aren't incorporated into functional and structural proteins are simply deaminated (their amino group is torn off). The amino group is excreted and the carbon skeleton can be oxidized for energy or converted to carbohydrate or fat for storage.

Since this reaction can't move in the other direction (amino acids aren't readily formed from carbohydrates and fats), aminos aren't stored in the body. So, if there's a need for amino acids in the body and there aren't enough aminos floating around in the blood from a recent meal, the body will destroy the structural and functional proteins for their amino acd content. This may mean the destruction of some of your hard earned muscle.

Because of these two factors, it's important to eat smaller protein meals throughout the day so you constantly have amino acids in the blood when the body needs them. Personally, I try to limit myself to a maximum of about 50 or 60 grams of protein in any given meal. Future research should give us clues as to approximately how much protein can be digested in a single sitting.

Glycerol: The Carb that Ain't a Carb. Or is it?

Q: I keep hearing about this glycerol stuff. On one hand I hear that it's a great diuretic to use when you're trying to look lean. On the other hand I've read that it's a carb source that's included in protein bars but not listed on the label by manufacturers. What's the deal with glycerol?

A: Before we get started, let's clear up a couple of things. Functionally, glycerol and glycerin are the same thing. So make sure you don't get confused and think these two names describe different things. Now, glycerol/glycerin is a naturally occurring compound (substrate) in the body. Structurally it's an alcohol but don't start dreaming up images of a "glycerol-buzz." It's not that kind of alcohol!

Glycerol/glycerin is a small and simple 3-carbon alcohol (by structure) that's produced in the breakdown or oxidation of nutrient substrates like glucose, protein, pyruvate, and triglyceride. Basically, when these larger substances enter degradation pathways they're "chopped up," forming smaller molecules. One of these molecules is glycerol/glycerin.

On the other hand, glycerol/glycerin can enter the synthetic pathways for triglycerides and glucose in order to make theses substrates. In fact, triglycerides are composed of the 3-carbon glycerol/glycerin backbone with a fatty acid attached to each glycerol carbon. So from this discussion, I want you to first recognize that glycerol is made from the breakdown of other substances but can also be used in the formation of other substances like fats and carbohydrates.

With that understanding, you can now realize that any dietary glycerol, while not technically considered a carbohydrate, certainly does have a caloric value (which means it provides energy). Since glycerol isn't technically a carbohydrate, fat, or protein, protein bar manufacturers often leave it out of the macronutrient listing. Since glycerol is technically an alcohol, they may not be completely unjustified, but it's so similar to a carb that the FDA considers it to be one and believes it should be listed on food labels.
So what are these manufacturers doing? Are they malicious hucksters whose goal is to trick us into eating their high carb bars? I don't know; maybe some are doing just that. Maybe some just don't know any better and maybe some believe the FDA is wrong. Either way, one important thing to remember is that the calorie total on the bar label is usually accurate. The label is just light on the carbs.

So if you want to "protect" yourself from deception, learn a little about food so you're not an ignorant consumer. Understand that when the carbohydrate, protein, and fat calories don't seem to add up to the total calories and when glycerol/glycerin is in the ingredient list, you've got some "alcohol" in there.
Now, this discussion so far has been only semantics; it's only a structural debate about glycerol. The important thing to understand is what glycerol does in the body. While not completely understood, a few things are clear. As described above, the body has a baseline concentration of glycerol floating around at all times. Blood concentration is about 0.05 mmol/L. These blood levels increase during the metabolism of fats and carbs.

For example, during the fat breakdown associated with exercise, this number increases six fold to 0.30mmol/L. The reason for this increase is that triglycerides are broken down to provide free fatty acids for energy. So when the free fatty acids are released, the glycerol backbone is free to travel to the liver where it's converted to glucose for even more energy. So here you can see that glycerol (and it doesn't matter whether it's from fat or from supplementation) can form glucose in the body.

Interestingly, when oral supplemental glycerol is taken (1g/kg), blood concentrations can increase up 400 fold from resting concentrations to reach 20mmol/L. It's been estimated that at rest, 30% of glycerol in the body can form glucose (via gluconeogenesis). So the remaining 70% can be used to form triglycerides and other substances. In this example, if a 90kg guy ingested 1g/kg of glycerol, he'd get about 30g of glucose out of it and the remaining 60g would form other substances like triglycerides. Remember, though, this is at rest. I'd speculate that during exercise, more glycerol would be turned into glucose and less into triglycerides.

So now you have two scenarios. If glycerol is ingested before or during exercise, you'd probably make a lot of glucose out of it and this glucose will be burned for energy. However, at rest, too much glycerol will form carbs and triglycerides. And if energy demand is low, these can be stored as body fat just like any other macronutrient.

Please don't misunderstand my point, though. I'm not saying glycerol will make you fat. In fact, glycerol is probably less likely to make you fat than carbs or dietary fat. My point is that glycerol, while not a fat or a carb, is used to make fat and carbs in the body or for energy.

With this said, I'd like to address your first idea of using glycerol for "losing water." I don't know exactly where this theory started, but I've also read people recommending relatively large amounts of glycerol for bodybuilders just before a contest. In my opinion, the research certainly doesn't support this practice. In fact, how could glycerol help make you "dry" when it's been used widely to increase body water?

When exercising in the heat, endurance athletes have been known to konk out due to dehydration and the inability to dissipate heat. This is due to loss of water and loss of blood volume. However, when taking glycerol, blood volume expands by 5 to 10% and total body water can increase up to about a liter (2.2kg). So these athletes are less likely to get dehydrated. This "hyperhydration" is due to a decreased urine production.

Some have speculated that this increase in body water is all increased vascular fluid. They speculate that water would be drawn from the subcutaneous space and the interstitial space and would go to the vascular system. This means that definition would increase, as would vascularity. However, pilot data in our lab has shown that body water increases everywhere (both intracellular and extracellular spaces) when taking glycerol and this is bad when you need to be as "dry" as possible. After all, you want to be relatively dehydrated for a bodybuilding show, not hyperhydrated.

Interestingly, a few days after glycerol supplementation, subjects tend to urinate like crazy and perhaps this "rebound" water loss could be used to a bodybuilder's advantage. Perhaps taking glycerol a few days before a show will create this sort of rebound water loss and competitors can come in "dryer" on the day of the show. We'll be testing out this theory in the lab soon. I'll keep you posted.

Eat This!

Q: In trying to make sense of your nutritional information, I've been having a hard time figuring out when to eat my protein/fat meals and when to eat my protein/carb meals. It's easy on my non-workout days; I simply eat four protein plus carb meals in a row followed by three protein plus fat meals in a row. However, on non-workout days I'm confused. Can you offer some help?

A: Your dilemma is not uncommon. It can get very confusing if you don't understand how the body works. In order to know how to design an eating program around your training, you need to learn how your physiology responds to different meal combinations at different times, then you have to apply this knowledge to both exercise and resting situations. Only then can you know how to eat to maximize training intensity and recovery while "keeping an eye" on your body composition.

So let's first go over some ways to optimize the physiological environment for growth and recovery while minimizing fat gain. After I address these considerations, we'll take a generic diet plan and adapt it to different training schedules.

As many regular T-mag readers know, my nutritional recommendations are based on a relatively simple concept: I recommend eating meals composed of only fat and protein, or meals composed only of carbohydrates and protein. I encourage weight lifters to avoid eating carbohydrates alone or meals that contain carbohydrates and fat. While this may seem "unbalanced" to some, the goal is to achieve a balanced proportion of macronutrients (30-40-30; 30-50-20; etc) at the end of the day.

I make these recommendations because there's some good scientific evidence (as well as quite a bit of anecdotal evidence) to suggest that such meal combinations can optimize the hormonal and metabolic environment of the body. This may lead to an enhancement of muscle growth along with decreased body fat levels.

When it comes to training days, I follow a few rules when designing an eating program using my meal combinations:

Rule #1 - Protein and fat meals should be consumed in the hours before training.

I believe that carbohydrate meals should not be consumed too closely to weight training workouts. If eaten about 30 to 90 minutes before exercise, such meals can cause immediate hyperglycemia and hyperinsulinemia and this can lead to a rebound hypoglycemia (decreased blood glucose) about 30 minutes later. With this drop in blood glucose, exercise performance may be impaired at the peripheral (muscle) or the central (brain) level.

Such meals may leave you feeling lethargic (like eating a high-carbohydrate meal for lunch) and affect your training intensity and mental outlook. Anecdotal evidence has indicated that weightlifters simply feel better when a protein and fat meal is consumed before training.

Rule #2 - Hydrolyzed protein and rapidly absorbed carbohydrates should be consumed during and immediately after training.

Although consuming meals that cause high blood glucose and insulin before training (30 to 90 minutes before) can lead to rebound hypoglycemia and compromise your training session, such meals that are rapidly digested and absorbed have a much different effect during the training session. Since your sympathetic nervous system is jacked during training, the lethargy I discussed before won't be a factor. In addition, the body does a nice job of maintaining blood glucose during exercise.

On the other hand, since blood flow to some muscles is increased dramatically during training (upwards of 200 to 300%), protein and carbohydrates that are rapidly absorbed will lead to a very anabolic environment. A large amount of glucose, amino acids, and insulin will be delivered to the muscle during such training and this may translate to muscle growth, even during training!

In one very recently published study, a drink containing free form amino acids and rapidly digesting carbohydrates actually lead to a net muscle gain during and immediately after training!

Rule #3 - Protein and carbohydrate meals should be eaten within the six hour period following training.

Basically, I believe that during the six hours following training, the body is most efficient at utilizing dietary protein and carbohydrates for muscle protein synthesis and muscle glycogen resynthesis. The combined hyperinsulinemia and hyperaminoacidemia seen with these types of meal combinations can lead to enhanced muscle gains and recovery when the body is best able to handle this influx of nutrients and insulin.

Rule #4 - Protein and fat meals should be consumed from six hours after training until the next training session.

After the six hour time point discussed above, insulin sensitivity and glycogen resynthesis potential may decline, especially if a good amount of muscle damage was accomplished. At this time, hyperglycemia and hyperinsulinemia can lead to glucose tolerance, increased fat storage, and a high propensity to block fat mobilization.

Although the body doesn't handle carbs as well as we'd like at this time, the damage has still occurred and this damage creates a high-energy demand for repair. So at this time, protein and fat meals can serve quite nicely in meeting this high-energy need. Since higher fat meals may increase the rate and/or amount of fat oxidation in such a situation, fat feedings may actually lead to increased fat mobilization from adipose tissues. Therefore, by timing your meal composition appropriately, you might be able to simultaneously recover from exercise, increase muscle mass, and decrease fat mass.

With these four rules in mind, let's go through an optimal eating plan. This plan consists of about 4200 calories at a 30% protein, 40% carb, and 30% fat ratio. As you said, on non-training days it's easy to come up with an eating plan. On these days the first half of your meals should be protein and carbohydrate while the second half should be protein and fat. However, let's add in a training session to see how the plan will change.

Feeding #1, protein plus fat (P + F) ,7:00am
3 egg whites
3 whole eggs
1/2 cup veggies
1 slice fat free cheese
2 tsp flax oil, 2 tsp olive oil

(Training Session)

Feeding #2, Workout Drink, protein plus carbs (P + C), 8:00am to 10:00am
1 L water
1.5 scoops Biotest Surge

Feeding #3, Post-workout Drink, P + C, 10:00am
1 L water
1.5 scoops Biotest Surge

Feeding #4, P + C, 12:00pm
1 banana
1/2 container cottage cheese
1 scoop protein powder
2.5 cups high fiber cereal

Feeding #5, P + C, 3:00pm
1/2 cup oatmeal
2 scoops protein powder
2 slices low fat grain bread
1 piece of fruit
1 piece fat free cheese

Feeding #6, P + F, 6:00pm
1/2 container cottage cheese
1 scoop protein powder
2 tsp flax oil
2 tsp olive oil
1 tbsp peanut butter

Feeding #7, P + F, 9:00pm
8 oz lean beef
2 tsp flax oil
2 tsp olive oil
1 piece of fat free cheese
Veggies

Feeding #8, P + F, 11:00pm
3 egg whites
3 whole eggs
1/2 cup veggies
1 slice fat free cheese
2 tsp flax oil, 2 tsp olive oil

So as you can see, there are four protein and carbohydrate meals and four protein and fat meals. These meals are scheduled optimally around the 8:00am training session and follow my four rules from above perfectly. Next, let's come up with an example where someone trains in the evening from 8:00pm to 10:00pm.

Feeding #1, P + C, 7:00am
1/2 cup oatmeal
2 scoops protein powder
2 slices low fat grain bread
1 piece of fruit
1 piece fat free cheese

Feeding #2, P + F, 10:00am
3 egg whites
3 whole eggs
1/2 cup veggies
1 slice fat free cheese
2 tsp flax oil, 2 tsp olive oil

Feeding #3, P + F, 1:00pm
1/2 container cottage cheese
1 scoop protein powder
2 tsp flax oil
2 tsp olive oil
1 tbsp peanut butter

Feeding #4, P + F, 4:00pm
8 oz lean beef
2 tsp flax oil
2 tsp olive oil
1 piece of fat free cheese
Veggies

Feeding #5, P + F, 7:00pm
3 egg whites
3 whole eggs
1/2 cup veggies
1 slice fat free cheese
2 tsp flax oil, 2 tsp olive oil

(Training Session)

Feeding #6, Workout Drink, P + C, 8:00 to 10:00pm
1 L water
1.5 scoops Biotest Surge

Feeding #7, Post-workout Drink, P + C, 10:00pm
1 L water
1.5 scoops Biotest Surge

Feeding #8, P + C, 12:00am
1 banana
1/2 container cottage cheese
1 scoop protein powder
2.5 cups cereal

As you can see from this example, there are a few exceptions to the rules above. Since the training session ended at 10:00pm, the post-workout protein plus carb meals are eaten until you go to sleep and then the extra meal is consumed the next morning for breakfast. Sure, it's not within the six hour window I discussed earlier and the carb utilization may not be as efficient, however, in this scenario you need to get those carbohydrates in there for muscle glycogen replenishment. It's better to get that extra carbohydrate meal in the next morning instead of neglecting it altogether.

I hope this description provides a good example of how to construct your own meal plans around your workout program. With the rules above, you should be able to eat as close to optimally as possible regardless of what time you train.