Fact Or Myth: Fruit & Contest Prep Don't Mix?


Fact Or Myth: Fruit & Contest Prep Don't Mix?
I will cite some of the theories why fruits are avoided by an unfortunately large number of bodybuilders and figure competitors and refute them. Learn more.
By: Ivan Blazquez
Fact Or Myth: 
Fruit & Contest Prep Don't Mix?
Ahhhhhhhhhhhh.... Fruits and their lack of abundance in contest prep, because of the common fear of fruits making us fat because of their high fructose content. But let us delve into this nutritional examination of fact vs. myth a little further. To the surprise of many, the truth to this issue is not very complicated.
To The Surprise Of Many, The Truth To This Issue Is Not Very Complicated.
+ Click To Enlarge.
To The Surprise Of Many, The Truth To
This Issue Is Not Very Complicated.

Fruits Don't Make You Fat
    First, I've never heard of fruits making anyone fat. Now this is an anecdotal statement, but now let me hit you with some knowledge (I stole this line fromBen Stiller in the movie Dodgeball). No actually, I want to inform you with proper and accreditable resources of information that will arm you to make a better decision in your future in regard to fruit consumption anytime of day and year.
    Eating fruits will not convert to fat nor make you fat.21 Now being the unbiased writer I am, I will actually cite some of the theories to why fruits are avoided by an unfortunately large number of bodybuilders and figure competitors in past years and sadly still today.
    Now the cool part is that I will actually refute these theories with concrete and tangible scientific literature and evidence to support fruit consumption anytime of day and year.
    The theory behind fruits stopping fat-burning is based on the muscles lacking an enzyme that converts fructose to glycogen. In fact, fructose is primarily found in high-fructose corn syrup, table sugar, fruit juice, honey and least in fruit and vegetables.5,32,61
    Now, if the muscle's lack this storing capability of fructose, then the liver is where fructose can be stored as glycogen. Well, unfortunately, the liver can only store 100-120 grams of glycogen,61 while the rest would be stored as fat. Ok, here is where extrapolation becomes more like Stretchapolation. In other words, to conclude fruits make one fat or prevent fat-burning or negatively impact body composition based off this logic, is simply wrong on all fronts.
To Conclude Fruits Make One Fat Based Off This Logic, Is Simply Wrong.
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To Conclude Fruits Make One Fat Based
Off This Logic, Is Simply Wrong.

Fruits And Fat Loss
    The logic to fruits being hazardous to body fat-loss goals is deflated by the two elements of body-fat loss maximization:

    1. Calories in vs. Calories out7,8
    2. Hormonal Power.28,29

    Burning fat is based on burning more calories than taken in and it is based on favorably altering your hormonal levels (insulin-to-glucagon ratio) to favor fat burning. The hormonal power is second in this list for a reason. First of all, the most important factor is calories in vs. calories out. Now, both are involved simultaneously as we will soon see.
    Typically, hormonal power food plans are based on low-glycemic carbs and higher protein intake with healthy fats. This favors bodybuilder goals because of a favorable insulin-to-glucagon ratio, but also because protein is kept normal to slightly above normal to prevent catabolism of endogenous protein and to promote caloric deficit since protein is the highest thermogenic nutrient.28,29,30
    These 2 approaches overlap simultaneously because most low-glycemic carbs are typically also of lower energy density, thus they naturally create a caloric deficit.
    Now, back to the main issue at hand, of how fruits can make us gain fat. Fruits do not make us fat in any way, shape or form. Fruits actually stimulate fat-burning further.18,19
    Here's the thing, most fruits are less than 100 calories to begin with,67 thus they are in favor with the 1st element of fat-burning,7,8,78 they are also mostly low-glycemic index.4,33
    Oh, if they are low-glycemic index because of the rationale of the fructose being converted and leaving the liver as fat and fat having a low-glycemic index, this is a flawed theory at best, considering the caloric density and fructose content of fruit is so small that this elevated fat in the blood would be trivial in regard to body fat storage.5,6 Furthermore, the body's storage of carbs to fat (de novo lipogenesis) is rather small.1,2,40,65
    Instead of fructose leaving the liver as fat, did it ever occur to the cynics that fructose leaves the liver as glucose!?37,44,61 In fact, research has clearly shown that fructose can be quickly converted to glucose from the liver and released for usage during exercise.37,44
    This glucose can also be either stored as glycogen in the muscles or be used readily for energy in the face of a caloric deficit as well.86
    This implicates the capability of the liver to use the fructose to convert it to glucose for energy use for itself and/or for the muscles or for glycogen storage for itself and/or for the muscles and of course lastly, for fat storage, which was shown to be the last resort fate of fructose.1,2,40,65 However, fat-storage would be the case for any nutrient (i.e. carbs, proteins and fats) in the face of a caloric surplus.7,8,40
Fat-Storage Would Be The Case For Any Nutrient In A Caloric Surplus.
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Fat-Storage Would Be The Case For
Any Nutrient In A Caloric Surplus.

Liver Glycogen
    Moreover, why is it presumed that liver glycogen is ONLY reduced upon waking up in the morning? Nothing happens in isolation; for example, liver glycogen is not just replenished in the morning and then it is full the rest of the day. This narrow-minded pseudo-science approach is what leads people to the feeling of being on a "diet" and nutritional deprivation.
    Liver glycogen is in a constant state of influx-efflux.63 After a bout of exercise, liver glycogen is not 100%, it is actually reduced and how much it is reduced will be determined on the intensity and duration of the exercise bout.61
    In fact, after each meal in a day, approximately 1/4 to 1/3 of the carbohydrates consumed are stored as liver glycogen, 1/3 to 1/2 is stored as muscle glycogen and the remainder is oxidized for energy.31 Research has shown that liver and muscle glycogen replenishment are enhanced with a mixture glucose and fructose versus each alone.16,23,74,90
    In other words, adding fruit to a post-workout shake will serve to enhance the post-exercise anabolic response.3,76,87 In addition, it was shown in a study that fructose actually improved the transport of branched-chain amino acids too!76 Actually, hydroxycitric acid is from the fruit, malabar tamarind.11,14,41,64
    Research has shown that glycogen replenishment is enhanced further with consumption of this fruit extract and fat storage is reduced.11,14,41,60,64Interesting, it was found that the extract from this fruit even reduced de novo lipolysis or conversion of excess carbohydrates to fats.55
    In fact, even if a little fat is made from excess fruit sugar (which I highly doubt, but let's play devil's advocate and go with this anyway), this may actually stimulate fat to be burned from stubborn body fat areas of the body! How? It's called, "Eat fat to lose fat".25 In other words, many times, the body will hit a wall in fat-burning (either by plateauing OR slowing down the metabolism if the caloric cut is too intense OR too long).
    This is where slightly higher carb and/or calorie days come into play by re-setting one's metabolism. And it is ok if you store a little fat during this 1-3 day period. Sometimes, we need to take 1-step back, to take 2-steps forward.
    There is research that has shown fructose to be more lipogenic than other sugars,13,73 however, in one study,73 85 grams of sugar was used in 1-meal and 50-75% was pure fructose (~43-64 grams of fructose)! Most fruit has anywhere from 4 grams or less per serving,10,32,66 while a large banana may have up to 7-grams.71
    What this study was alluding to was the increased consumption of fructose sweeteners or added fructose sweeteners such as high-fructose corn syrup that are produced from corn starch and other starches.5
    In fact, another study did establish that fructose from fruit is not the culprit, but it is the added fructose to food.38 We need to get back to the basics of healthy-whole food eating.
Adding Fruit To A Post-Workout Shake Will Serve To Enhance The Post-Exercise Anabolic Response.
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Adding Fruit To A Post-Workout Shake Will Serve
To Enhance The Post-Exercise Anabolic Response.

Fruit Is Good For You
    Another great thing about fruits is they are very healthy for us15,21,26,27,35,47,51,56,58,62,72,83 and they are packed full of carotenoids, flavonoids, antioxidants20,21,36,48,79,81,89,91 and many of the essential micronutrients we so desperately need.
    In fact, research has shown in the past that bodybuilders are typically deficient in many nutrients and minerals during contest prep.42,68,86
    Fruit is a high-volumetric food because fruit is rich in water and fiber.21,77 The skin of most fruit contains a significant source of fiber and antioxidants and the fruit itself is so gratifying to anyone with a sweet tooth or sugar cravings, , that to deny them could be detrimental to one's emotional health.
    Contest prep is tough and challenging, but my point is, it does not have to be unhealthy or so deprivative. In fact, research has shown that low-carbohydrate ketogenic diets have no advantage over nonketogenic low-carbohydrate diets.49
    It has been shown that ketogenic low-carb diets are associated with adverse metabolic and emotional effects.49 Research has shown that bodybuilders tend to complain about feeling vertigo, whole body fatigue, aches, lack of energy and depression during contest prep.68,85
    So when I hear or read about how it gets so tough during contest prep because of cutting carbs (particularly fruit), I realize how vanity is placed before healthy living.
The Skin Of Most Fruit Contains A Significant Source Of Fiber And Antioxidants.
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The Skin Of Most Fruit Contains A
Significant Source Of Fiber And Antioxidants.

What About The Fructose?
    Additionally, fruits are not 100% fructose. It is shocking how fruits have been deemed as being bad for us by some, because of their naturally-occurring fructose content. Fruits are actually a brilliantly complex and seductive combination of fructose, sucrose, glucose, galactose and maltose.70
    Even so, not all fruits are created equal. For example, even for the hardcore bodybuilder who still avoids fruit in the last 1-2 weeks out, thinking this will get them to an absolute peak, I have a nice compromise. If you are concerned with the little fructose in fruit being stored as fat, one could simply eat higher fructose fruit in the morning for breakfast and eat lower-fructose containing fruit later in the day.
    All things considered, the highest fructose containing fruits typically have 4-5 grams of fructose anyway. This would mean 4-5 grams equals 4-5 grams of fat right? Not so fast. Fat is 9 calories per gram, so theoretically, the 4-5 grams of extra fructose would mean a mere 1.7-2.2 grams of fat stored or 15-20 calories stored as fat.
    Now, going back to the 1st element of fat-burning, if one is in caloric deficit, even if this trivial/meager amount of fructose is converted to fat, it will not be stored as fat because your body is already in negative caloric balance. This means you will use this fat for energy.
    This also explains how bodybuilders can get down to extreme levels of leanness and then begin to eat more fat and/or carbs to "fill-out." They are still in negative balance, so fat theoretically becomes partitioned in favorable ways (used for energy and/or stored as essential fat or intramuscular fat).
    The intramuscular fat part probably explains one aspect of how one can "fill-out" and still be lean when slowly adding calories back into the diet in the last 1-2 weeks. The body thinks, "Well, this man/women is really physically-active, I'd better store this fat close to the muscles so he/she will use it readily for energy for his/her next workout," metaphorically speaking.
    Also, when fructose is converted to fat, like any conversion of carbs to fats, there is an energy cost in this conversion process.30,43,45,50,75 For example, for every 100 excess calories of protein, ~ 60-75 calories are stored as fat, while for every 100 excess calories of carbs, only ~ 72-76 calories are stored as fat, whereas with fat, ~ 97-98 calories out of 100 are stored as body fat.
    So even if the carbs convert to fat, this is a costly process and you will likely store ~72-76% of the excess carbs as fat. So for those who have higher fat intakes on a low-carb diet, that is just mind-boggling because as much fat as you will be burning, you will be storing, so you're fighting a never-ending battle,50,80,82 not to mention, muscle catabolism is greater when carbs are not at a minimal level of sufficiency.57
The Highest Fructose Containing Fruits Typically Have 4-5 Grams Of Fructose.
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The Highest Fructose Containing Fruits
Typically Have 4-5 Grams Of Fructose.

Great Contents Of Fruit
    Another important aspect of fruits is, they contain many of the muscle-building and repairing nutrients we need like potassium,22 vitamin A,9,59vitamin C46,49 and other antioxidant compounds known as phytochemicals such as bioflavonoids [catechins, tannins], limonoids [detoxification] and lycopenes [antioxidants].53
    More importantly, many fruits have even been found to stimulate fat-burning77,84 and promote muscle-mass gains!22 Actually, many of the top fat-burners out there in the market have fruit extracts in the ingredients.
    For example, grapefruit has narginen, one of the ingredients that promotes fat-burning.34 Furthermore, I researched this and found grapefruit actually has a relatively high amount of HMB!88 This is the metabolite of leucine that has been shown to promote muscle mass accretion.69,88
    And finally, I recently presented my master's thesis for publication at the 56th Annual American College of Sports Medicine Science meeting, and learned from a fellow colleague that grapefruit has 6',7'-dihydroxybergamottin (6',7' DHB), which has been shown to increase testosterone production!24
    Another fruit, which was mentioned earlier, is the malabar tamarind. It contains hydroxycitric acid, which is a common ingredient in many fat-burners due to it's ability to enhance partioning carbs to glycogen and inhibit new fat synthesis.11,14,41,55,60
    It is amazing how when I read the back of many fat-burning supplement labels I see the following, but not limited to: Red raspberry extract, blueberry extract, cranberry extract, etc. It is amazing how many of the bodybuilders and figure competitors who avoid fruits are actually spending all this money in consuming the same extracts that come from the fruits they are actually avoiding on a daily basis!
    Even more amazing, these extracts are probably more bioavailable and potent in natural form from the fruits.39,54 There is a certain synergism that can not be replicated in a pill.17,39,54
    With every issue, there are caveats of course. For example, the only reasons for supplementing with a fruit extract would be if that fruit itself was not available in grocery stores, if one is lactose-intolerant, if one has certain food allergies, if one is a vegan and if one diets poorly.17 For example, malabar tamarind among many other extracts, is not available where I live, so this would be an acceptable compromise to consider supplementing.
Grapefruit Actually Has A Relatively High Amount Of HMB.
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Grapefruit Actually Has A
Relatively High Amount Of HMB.

Bottomline:
Fruits are low in calories, high in nutrient power and curb sugar cravings the natural, but more important, the healthy way. I avoid saying the right way, because there is typically no one way to reach a goal or destination. However, it can easily be said that including fruits in your eating habits year round is going about things the healthy way. And with this, you will rest assure that you are not only looking your best, but also feeling your best!
Actually, this article was finished, but I just remembered something else! Many skin care products (i.e. moisturizers, shampoo, conditioners and body exfoliants) contain fruit extracts. So actually, fruit will not only make you feel your best, you will also look even better than your previous best!
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Mario Lopez Is A Fitness Machine: Q&A With Super Mario!


Mario Lopez Is A Fitness Machine: Q&A With Super Mario!
Mario Lopez is an accomplished actor, a successful TV host, and a genuine fitness phenom. Get the scoop on how Mario juggles fame, fun, and a six-pack.
For every Mario Lopez, there are 100 child and teen actors who never made it off the silver screen, never escaped the typecast of their first TV gig. So what made Lopez different? He took chances, did TV movies, exercise videos and reality shows. Through the downs, ups, Nips/Tucks, one constant held it together for Mario. He never lost that "wrestler's body" that made him an adolescent star. He changed over the years, adapted roles. His body and career matured together.
With maturity comes confidence. Mario took a chance, leapt off the stage on onto the set. He hosted pageants and competitions, read teleprompters and got the hang of commentary. Now, as host of Extra! on E! he can work and live the Hollywood life through the lens of celebrity news. Constant fitness was once but an asset, a single trait to this actor. Now, his physique may be his great fame claim. He is a genuine fitness machine, with perfect muscle symmetry and grappler's agility. Lopez' pep and personality make him a fine actor/TV host, but for the last 25 years, it was his fitness which allowed him to become a star.

Q&A with Super Mario

Mario Lopez

Frank Sepe:

Many celebrities have written books on fitness and nutrition, and in a lot of cases, they are very hard to take seriously. You get the feeling that they are just trying to make a fast buck.
That is not the case with you at all. You have always been consistently admired for your physique, and rightfully so! It seems like you are very passionate about living a healthy lifestyle. Who was it that inspired or put you on the path to this way of life?

Mario Lopez:

I have to thank my parents for making sure I was either outside playing or for putting me into sports as a kid. I wasn't one to sit around watching TV, and I'm so thankful to my parents for always encouraging me
to be active.
Over the last 30 years, obesity rates have tripled for kids. As a future father, what types of healthy values will you teach your kids?
Just to have fun, use your imagination and be competitive. Seriously, I think one of the best parts of growing up was competing with other kids and having pick-up ball games outside.
My kids will be active in one way or another, but then from an eating standpoint, they're going to learn the value of sensible portion sizes. Honestly, when you pair fun and active lifestyles with reasonable food choices, good things happen.
Millions of fans love you as super buff wrestler "AC Slater" on the hit TV series Saved by the Bell. But, truth be told, you actually did wrestle in high school. What kind of training fundamentals did you learn from wrestling, and do you still use some of that old school workout in your current routine? Wrestling definitely helped me form my foundation - a base - if you will. But I truly believe my wrestling days help me now in many ways, and not just from a physique standpoint; a kid learns what he's made of when he's down on the mat. To be honest, I'd say the intangibles are what I think about most when I remember my wrestling days.
You have been successful in a multitude of entertainment endeavors in your career,and through it all, you have always kept your body in top shape. You could probably come up with some legitimate excuses for not eating healthy or skipping a workout with the demands of your work schedule. So, what is it that inspires and drives you to want to keep taking your body to that next level when others are content to stay status quo?
You know, staying healthy is a top-of-mind thing for me. It's woven into my DNA, I guess you could say. I just feel I'm at my best at work and at play when I'm taking care of myself physically. And I'm never satisfied, I think that helps. I always want to improve and get better. Whether I'm boxing, running or lifting weights, each day I look for a challenge and get after it.
I understand you have some serious boxing skills and that you have sparred against Golden Boy Oscar De La Hoya, James Toney and Shane Mosley. What did you learn from being in the ring with these guys? Do you think you could have been a good pro boxer? Did you taste some leather?
Well, I've had the pleasure of meeting and sparring with some really special fighters.And I think what I've learned most from being in the ring with legends is that I have a lot to learn, but that's why I love sparring with people much better than me. It only helps me get better. As far as me being a pro boxer, who knows? All I know is that I love the sport.
KO! Mario has a ring-worthy physique.
KO! Mario has a ring-worthy physique.
Speaking of boxing, I know that you are an analyst for Top Rank promotions. If you don't mind being put on the spot, who do you think would win in a Manny Pacquiao vs. Floyd Mayweather fight and why?
Well, I know both of them very well, and they're probably the two best fighters out there. It's a good question ... Let's just say it would be a great fight and if it happens, I'll be ringside.
What type of music do you listen to when you work out?
I listen to all types of music, but I love 80's, hip-hop and house music.
You are considered by many to have the perfect physique. When you hit the gym, are there any body parts you work out harder because you feel they need improvement, or are you more into athletic performance?
Sure, I do body-part-specific training each week, dedicating entire sessions to, say, chest and arms, or back, but I also like to mix it up and shock my system. So yes, from one day to the next, you might find me in the squat rack working legs or in the middle of the ring sparring or swimming laps in the pool.
You look better today, in your 30s, than you did in your 20s. How has your fitness regimen changed from the past?
I'd say it's much more educated. About 5 years ago, I was introduced to fitness expert and author Jimmy Peña. Not only is Peña one of my best friends, he's taught me so much about training and nutrition. Whenever I want to get "dialed in" for a photo shoot or specific role, Peña is my only call. As you know, he and I wrote Extra Lean together, and we're so fortunate for the success and response it has received. And there's more to come with Extra Lean, so be looking out for that.
What is your fitness philosophy?
It's really kind of simple: Find something you love to do and fight to improve each day. If you love to play at it, you'll work hard at it.
Can you give us a breakdown of how many days a week you train and what forms of exercise you do on those days?
I'd say I train 6 days a week. I have to force myself to rest; probably my biggest training mistake. And like I said, I do everything. If I'm not in the weight room, I'm either sparring or swimming or taking my dog, Julio, for a run.
You have a ot of fans out there wondering what the secret to your 6-pack is.
It's really a combination of things. I do weighted abdominal moves, targeting the upper and lower abs as well as the obliques, but I also do high-rep bodyweight-type moves to fatigue. But truthfully, it all comes down to diet. Training will absolutely help develop a 6-pack, but if you're not eating clean, nobody will ever see it.
How do you fuel up before a workout?
I like to have a complex (slow-digesting) carb like oatmeal or Ezekiel bread, and a quick-digesting protein like whey about 30 minutes before I train. I don't like to be full or hungry during a training session, just satisfied.

What do you eat after you train?
After I train, I believe it's critical to refuel, so I'll hit another whey shake, but I'll hit some faster-digesting carbs to replenish my system, like a sports drink or even white bread.
You have such a busy schedule, what is a typical day of eating for you like and what do you say to those people who claim they are too busy to eat healthy?
The key to eating healthy while accomplishing your goals on a busy schedule is to always have food at-the-ready. I suggest trying to prepare food the night before and keep it with you. If entire meals are tough to prepare and carry, make sure that you have two or three easy-to-eat snacks with you throughout the day.
You have a successful book titled Extra Lean: The Fat-Burning Plan That Changes the Way You Eat For Life - What is the most important message in that book?
Thanks, yes - so excited about Extra Lean. The great thing about Extra Lean is that it helps people realize the importance of eating all kinds of foods (proteins, carbs, fats), all throughout the day. The portion sizes I want people to eat are drastically different than how they typically eat nowadays, but overeating is a major problem facing our country. And since I'm such a big foodie, I'd rather cut portion sizes than remove taste - And you really can get lean while eating delicious food.
Would you mind sharing one of your favorite healthy recipes with us?
They're all delicious, but you've got to try my fish tacos or even my chicken enchiladas. They're so good.
Thank you for the interview, it was a pleasure speaking with you, and I would like to recommend for all of our readers to go out and get a copy of Mario's new book, Extra Lean: The Fat-Burning Plan That Changes the Way You Eat For Life.
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Leucine: Build Muscle With This Anabolic Amino Acid


Leucine: Build Muscle With This Anabolic Amino Acid
Leucine, a branched chain amino acid, is a protein stimulus gunslinger. Find out how it works and pull the trigger to build more muscle!
Look around the gym and you'll see as many different body types as there are dumbbells. There are giants roaming the weight room, skinny guys on the treadmill, and maybe even some ripped sprinters hustling hard. One reason for these different body types? Different training methods. Different forms of exercise have different training effects, and they affect protein synthesis in different ways.
Protein synthesis is the creation of new skeletal muscle proteins. When this occurs on a large scale, it is known as skeletal muscle hypertrophy (growth), and it's the process by which our muscles get bigger. Before we dig into how to maximize protein synthesis and the unique role of leucine (a branched chain amino acid), let's cover a few basics.

Protein, Exercise And You

Endurance exercise affects skeletal muscle protein turnover by decreasing the rate of skeletal muscle protein synthesis and increasing the rate of protein degradation (muscle breakdown) 1. Thus, endurance training can eventually build the super-skinny or overweight pavement-pounders who run 40 miles per week.
Resistance exercise is unique because it actually elevates skeletal muscle protein synthesis AND increases the rate of skeletal muscle protein degradation. The overall effect, in both cases, is a negative net protein balance 2. During resistance exercise (i.e. training with weights, bands, and/or other torture devices) your body goes into a catabolic condition; at rest, your muscles repair and increase in size. Kapow: Arnold arms!
That is, if you get enough post-workout protein. In order for protein balance to become positive post-workout, dietary protein - and specifically the amino acidleucine - must be consumed.
In fact, protein balance will remain negative until protein is consumed 3,4.

The Power of Protein

Anyone who has ever read a muscle magazine or talked to a meathead long enough knows that consuming a diet high in protein is one of the major ways to maximize muscle gain. That's because protein is essential for muscle growth. Protein is made up of amino acids, the ingredients that stimulate muscle protein synthesis. There are over 20 amino acids that occur in the dietary protein we eat, but not all of them have the same impact on muscle growth.
The amino acid leucine is the king of stimulating muscle protein synthesis!

Leucine, I'm Home!

Leucine is one of the three branched chain amino acids (BCAAs), and is unique in its ability to stimulate skeletal muscle protein synthesis. In fact, leucine has a several fold greater impact on protein synthesis than any other amino!
Leucine activates a major complex in the anabolic (muscle-building) pathway called mTOR 5-7. Think of mTOR as the amino acid sensor of a cell. mTOR is sensitive to leucine concentrations. Decreasing leucine concentrations signal to mTOR that there is not enough dietary protein present to synthesize new skeletal muscle protein, so mTOR deactivates. Increased leucine levels signal to mTOR that there is sufficient dietary protein to synthesize new skeletal muscle protein, so mTOR "turns on."
Though researchers are not sure exactly how leucine activates mTOR, it has been shown that mTOR is sensitive to leucine concentrations and activation of mTOR is strongly associated with increased protein synthesis, which means more muscle growth.
mTOR increases protein synthesis through two different mechanisms 8. It increases the rate that skeletal muscle proteins are translated (process by which genetic information is converted into protein), and it increases the production of different complexes in the protein-synthetic pathway, thereby increasing the body's capacity to stimulate skeletal muscle protein. So, not only does mTOR stimulation cause the body to create new muscle tissue faster, but it also increases the amount that can be produced in a period of time! Sweet!

Making Sense of mTor

Did I lose you? Here's an analogy: The contracting company mTOR is building a protein skyscraper. The machines (bulldozers, cranes, etc.) are the protein synthesis pathway components, and leucine is the cash needed to make the project work. When enough cash is available (increasing leucine concentrations), the contracting company can start building the skyscraper (synthesizing muscle protein) and also purchase more machines (increased synthetic components). This increases the capacity and speed at which mTor can construct the skyscraper (the muscle protein being synthesized).
To build protein skyscrapers (muscles) in our bodies, it's clear that leucine is a necessary component. The question, though, is whether it's beneficial to supplement with extra leucine, or if we get enough from a high protein diet? There is some evidence that supplemental leucine may be beneficial, even if one ingests ample protein.

Supplement Scrutiny

In a recent study, subjects did resistance training for 45 minutes. After, one group of them supplemented with carbohydrates, another group with carbohydrates and protein, and the last group supplemented with carbs,protein and leucine.
Researchers found that the carbohydrate/protein/leucine supplement group reduced muscle protein breakdown and increased muscle protein synthesis to a greater degree than the carbohydrate/protein group, and to a much greater degree than the carbohydrate-only group9. Thus, more leucine might equal more muscle when added to protein and carbs!
As a free-form supplement, leucine gets absorbed into circulation much faster than when it's part of a whole protein. Even with a fast-digesting protein such as whey, it can take hours for the leucine to be liberated from the protein and enter circulation. Therefore, leucine concentrations in the blood never spike to high levels. An isolated leucine supplement, however, would be quickly absorbed into circulation, thus spiking blood leucine levels and drastically increasing intracellular leucine concentrations and activating anabolic pathways.
For those who are dieting but want to maintain maximum muscle mass, a leucine supplement may help alleviate some of the catabolic effects of a calorie-deficit diet. Leucine is more anabolic than other amino acids. While this hasn't been studied in detail, it might be possible to substitute something like 5g of leucine for 30-40g of dietary protein and still have the same or greater stimulatory effect on muscle protein synthesis.
Again, this is a hunch of mine based on current research and my own PhD work. With a leucine supplement, you may be able to maintain high levels of protein synthesis and knock an extra 100 calories off your diet. Can you say, "shredded?" (You don't have to say it. Just be it.)

Leucine Lowdown

In conclusion, it's clear that leucine increases protein synthesis by increasing the activity of mTOR. Leucine has a far greater stimulatory effect on protein synthesis than any other amino acid. Protein synthesis increases similarly in response to a relatively small dose of leucine compared to a whole food meal. Also, adding leucine to a protein-rich meal further increases the rate of skeletal muscle protein synthesis.
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