All posts tagged metabolic

Macronutrients In Every Meal

I always say that the term “healthy diet” is a political term.  After all, the USDA Food Pyramid is nothing but politics.  Whoever lobbies the hardest, or pumps the most research into biased “scientific” studies gets their desired place on the pyramid.  Of course, things are getting better (in my opinion), in regard to the pyramid, but we still have a long way to go when it comes to promoting quality and strategy.

Without going into another rant about denatured “bastardized” foods available on the market, I’d like to write about the roles of macronutrients in the diet, and how they should be a part of every meal.

A macronutrient is an essential substance required in relatively large amounts by a living organism.  A micronutrient, on the other hand, is a substance required in relatively small amounts–like vitamins and minerals.

What qualifies as a human macronutrient varies according to who’s talking about it, but the list looks something like this: fat, carbohydrates, protein, fiber, and water.  In this article, I will focus mostly on the first three.  By focusing your attention on the first four, and eating them from quality sources, as few people need a better understanding of water.

Fat (Lipids)

Fats/lipids are a group of compounds that are generally soluble in organic solvents and generally insoluble in water.   The include triglycerides, phospholipids, and sterols.  In the diet, 95% of lipids are fats and oils (in the body, 99% of stored lipids are triglycerides, that is, three fatty acids attached to a glycerol backbone.

Fatty acids come in three forms: saturated, monounsaturated, and polyunsaturated.  These levels of “saturation” are determined by how many hydrogen atoms are attached to the chain of a particular fat–and chains vary in length as well.

No need to concern yourself with the chemistry.  Think of it this way: saturated fats are solid at room temperature, unsaturated fats are liquid.  Keep it simple.

Lipids are the most concentrated source of energy, packing 9 calories per gram (because of this, many people try to avoid fat in order to lose weight, since it is easy to overeat on certain types of fat).  Fats are involved in the following:

  • Cellular membrane structure and function
  • Precursors to hormones
  • Surrounding, holding, and protecting organs
  • Regulation and secretion of nutrients in cells
  • Insulating the body from environmental temperatures and preserving body heat
  • Initiating the release of the hormone cholecystokinin (CCK), which contributes to feelings of satiety*
  • Prolonging the digestive process by slowing the stomach’s secretion of hydrochloric acid*
*Fat is digested and absorbed quite slowly (by without great digestive effort), and therefore remains in the stomach longer than carbohydrates or proteins.  For this reason, it leaves you feeling fuller, longer.  When you eat fat, it’s like throwing a big log on the fire–it is slow to burn, and gives you hours of lasting, consistent heat (energy).

Protein

Proteins are polymer chains of amino acids linked together by peptide bonds.  They must be broken down into their separate amino acids before the body can make use of them.  Of the 20 essential and nonessential amino acids, only 8 essential amino acids (ones the body cannot make on its own) are necessarily derived from the diet.

A “complete” protein is any protein source that contains all 8 essential amino acids.  Animal sources of protein are complete–plant sources are often incomplete (or low) in some amino acids.

Amino acids from protein are needed for the following:

  • Synthesizing body-tissue protein
  • Providing glucose for energy (if needed)
  • Contributing to fat stores (not always)
Amino acids will not be used to build protein if:
  • There is not enough available energy from carbohydrate or fat
  • If essential amino acids are lacking or consistently too low
  • There is an excess of too much necessary protein (and they will be excreted from the body instead)
Chronic high protein intake diets can lead to:
  • Calcium depletion
  • Fluid imbalance
  • Hunger
  • Slower metabolism (due to insufficient fat and carbohydrates)
  • Energy loss
Protein is found in the majority of foods.  While animal sources are “complete,” plant sources are cleaner sources of protein, promote better health, and should never be discounted.  In any diet, it is important to consume a variety of foods, in order to consume a variety of vitamins and minerals.  Under the same concept, it is important to consume a variety of plant foods, to ensure a variety of essential amino acids–if one chooses a meatless or vegan diet.
With each meal, be sure to have a variety of foods, to ensure sufficient amino acid consumption.
Carbohydrates
Carbohydrates are the chief source of energy for the body and all of its functions.  They are compounds consisting of a carbon, hydrogen, and oxygen.   They fall under three classifications: sugar, starch, and fiber.
Sugars are carbohydrates, and they come in two forms: monosaccharides (single units–glucose, fructose, galactose) or disaccharides (double units–sucrose, lactose, maltose, etc.).  Sugars digest quickly and are typically burned up rapidly in the blood stream and by the brain, unless consumed in excess .
Multiple sugars can connect together to make starches–longer chains of carbohydrates.  These typically take longer to digest (unless “pre-digested” through processing), and provide longer, steadier burning energy.  Starches, particularly refined ones, are easy to over-consume and as result, contribute to fat storage.
Because they are the chief source of energy for the body, rapid depletion (burning) of carbohydrates, or carbohydrate restriction, will lead to continual cravings for this macronutrient.  
Fiber is a non-digestible form of carbohydrate and is essential for optimal health:
  • It provides bulk in the diet, thus increasing satiety (some fibers delay the emptying of the stomach, subduing a potent hunger hormone, ghrelin)
  • Prevents constipation
  • Maintains good intestinal mobility
  • Aids in prevention of bacterial infections
  • Reduces risk for heart disease by lowering blood cholesterol (certain fibers bind with cholesterol compounds and sweep them out of the body; may also inhibit production of bad cholesterol)
  • Regulates body’s absorption of glucose (sugar)
With every meal, it is important to include a carbohydrate that has not been stripped of its fiber.  White flours, added sugars, and peeled starchy root vegetables should be avoided, as the removal of fiber adulterates normal digestive breakdown of these foods, leading to numerous metabolic externalities within the body.  Never remove the fiber from food.
In Sum:
Every meal should be eaten in balance.  Carbohydrates, fat, and protein should be eaten with every meal.  This ensures slow, consistent digestion and energy throughout the day.  Carbohydrates should not be avoided, as they are the body’s primary fuel source.  Avoid carbohydrates that have been stripped of their fiber.  Fat should accompany the meal, to slow the digestive process and increase levels of satiety.  Protein is present in most foods, but it is important to eat a variety of foods, so that all essential amino acids can be obtained (as well as vitamins and minerals).
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by demogirl06 on October 27, 2011  •  Permalink
Posted in Nutrition
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Posted by demogirl06 on October 27, 2011

http://mariamaestevens.com/2011/10/27/macronutrients-in-every-meal/

Training Your Metabolic Pathways: Q & A

***The following Q & A is a continuation from my previous article, Training Your Metabolic Pathways (part 1).  Readers are encouraged to see the article (which explains how different energy systems work and how to train them) before reading this article.***

Okay, so what if your goal is to reduce your body fat?

Q: Why not train the first system, aerobic liposis, to ensure that all the calories being burned are coming from fat?

A: Because you have seemingly unlimited fat stores.  If you don’t deplete your glycogen stores, and happen to eat a little more, all of those extra calories will go into fat storage, since the glycogen tank is full.

Q: Why train so hard, in the glycolitic systems, all the time?

A: More bang for your buck.  In terms of calorie-burn per minute, the glycolitic systems win over the lipolitic system.  You don’t have to be in the gym nearly as long to burn calories.

Q: So what…?

A: If you are constantly depleting your glycogen fuel tank (which can hold 1,500 to 2,000 calories in the average person), you have a “free food window,” meaning… if you happen to overeat a few hundred calories of carbs, you can be guaranteed that they will simply go into glycogen stores, rather than fat storage.  This is how calorie deficits works.  As long as you keep your window “open,” it is difficult to gain weight from eating too much (unless your diet is very out of balance).

Q: Okay, so as long as I keep my glycolitic fuel tank half full…

A: You’ll be all right unless you’re bombing on pints of Haagen Dazs, blocks of cheese, and other high fat foods.  Your body only needs so much fat, and can only use so much as energy.  Eat too much, and it tends to go into storage.

Q: So if I train my aerobic glyocolitic system a lot and keep my “window open,” isn’t that enough?  Do I have to do all those nasty intervals and tough strength training sessions?

A: As I said before, more bang for your buck.  The higher the intensity, the more calories per minute you burn, and hence the wider that “window” is.  But, even better, if you train your body hard, you can increase the amount of glycogen that can be stored!

Q: Really?  How?

A:  Just as the body will make bigger muscles after a strength training session to be more prepared for the next time you place that kind of demand on them, the body will upgrade to a bigger fuel tank, in order to be more prepared for your habit of stepping on the gas all the time.  Conditioned endurance athletes can store up to twice the amount of glycogen compared to normal people (there is, admittedly, a genetic component to that as well).  So the more you condition your glycolitic systems, the more you keep your window open, and the bigger that window gets.

Q: Okay, so I train my aerobic glycolitic system a lot, and the idea of getting a bigger window (a bigger fuel tank) is nice, but I don’t worry that much about overeating.  So still, why bother with the anaerobic glycolitic system?  I can’t maintain my anaeobic intensity as long as  I can maintain my aerobic intensity anyway, so at the end of 40 minutes, I will have burned more calories than I will have burned in 15-20 minutes of anaerobic work.

A: Good question.  I have a two-part answer for you.  First, if you want to lower your body fat percentage, you can burn off some of your fat, you can put on more muscle, or you can do both.  Intervals aren’t the only anaerobic activity.  Resistance training also trains the glycolitic anaerobic system.   By adding more muscle, you lower your body fat percentage–but not necessarily your absolute body fat (amount of pinchable fat).

Q:  So I’ll still be fat, only with bigger muscles underneath?

A: If you eat too much, yes.  If you always eat enough to shut your glycogen “window” (fully replenish your stores) and something extra, your body will have no incentive to burn fat.  but remember, one pound of muscle, we have all heard, requires way more calories to maintain than one pound of fat.  Muscle requires protein, of course, and it stores glycogen, but during your day-to-day activity, your body will burn more fat to power itself.

Q: How much more?

A: A few tens of calories per pound.

Q: Is that it? A few tens of calories?

A: Well… yes.  But think of it this way, if you put on 5lbs of legitimate muscle over a few months and then just maintain it, that can be up to 150 extra calories burned per day.  That offsets fifteen pounds you could have potentially gained in a year.  Believe it or not, 10 lbs of weight gain per year can be quite normal for an adult.

Q: I guess that is a nice safety net.  But I want to drop my body fat now!

A: Then the most relevant thing to you is something commonly called “afterburn.”

Q: What’s that?

A: Afterburn is the amount of energy you use after your workout.  When you train at a very high intensity, your metabolism races.  When you’re done, it’s still going hard.  Imagine a car… you cruise in your car for a half hour, then park it in the garage.  It cools down eventually.  What if you red-lined that car until it overheated?  It would take much longer for the engine to cool down.  Same idea.   If you do some aerobic work at the gym, then hit the locker room, leave and head to a cafe to read, you click back into your day-to-day mode pretty easily.  But if you bust it at the gym, it takes much longer to relax, and maybe later in the day your muscles start humming.  Repair, repair, repair!  Replace, replace, replace.  These are highly metabolic activities.  You want to work hard at the gym often, to the point that your afterburn is apparent even to you.

Q: Okay, so every time I feel like hell after a workout, that’s a good thing?

A: That’s when the most weight loss and body re-composition happen, other than when you are sleeping.  The more you have to repair and replace all the time, the faster your body shape will change! And frankly, when you get off that treadmill or elliptical machine, you really haven’t done very much damage, even if you were pushing it.

Q: Riiight… I guess that makes sense.  So I just have to accept the fact that most of my workouts are going to be painful.  But who in their right mind wants to do something that hard all the time?

A: Pain and difficulty are relative feelings.  The more you challenge your body, the less it hurts in the long run, and the less difficult it is to confront.  Something that hurts and burns in one person feels completely manageable, if not comfortable, in another person.  Over time, as you become more fit, things hurt less.  That is fitness.

Q: But if things hurt less, then isn’t it harder to burn and break?  Won’t it be more difficult to challenge myself?

A: On the contrary, the more conditioned you become, the more you can take on.  The higher you raise your anaerobic-lactic acid threshold, the more reps you can squeeze out, the longer you can go, the more “damage” you can do.  Here’s an example.  You can work your anaerobic system by doing three sets of 12 dead lifts.  If you’ve been lifting for a while, you’re not likely to be super-sore afterwards.  Or, you can work your aerobic glycolitic system by doing over 100 dead lifts as fast as you can, at a lighter weight.  The end result is a bobble between aerobic and anaerobic, more reps, and hence more time your muscles are under strain.  You’re likely to be quite sore after that effort.

Q: Take-home lesson: always look for new ways to challenge myself.

A: One more thing.  Just as you train your energy systems to exercise, by exercising, you train your at-rest energy systems.  When you keep your glycogen stores perpetually half full, and your body is constantly trying to convert carbohydrates into glucose to re-fill them, the rest of your body relies more heavily on fat stores to power you through the day.  The more you exercise, the more fat you burn at home, period.

See you at the gym!

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by demogirl06 on July 13, 2010  •  Permalink
Posted in Exercise Physiology
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Posted by demogirl06 on July 13, 2010

http://mariamaestevens.com/2010/07/13/training-your-metabolic-pathways-q-a/

Training Your Metabolic Pathways (part 1)

Here’s a crash course in exercise physiology.

Whatever you eat, and however you exercise, your body ultimately gets its energy from a molecule called ATP, which stands for adenosine tri-phosphate. Imagine a little three-leaf clover; each leaf is a phosphate.  Your body pops one of these leaves and energy is released, rendering that clover a di-phosphate (only two phosphates are left).  Your metabolism looks around for something to replace that third leaf.

You may think that you get energy from calories–”fuel”–and that you burn whatever goes in when you’re exercising.  While this is true in a broad sense, it is far more complicated than that.  The metabolism (the rate/way in which you burn energy) is a very sophisticated and complex thing.  It is dynamic, and it has different strengths and weaknesses, depending on who you are; it can also be trained and adapted, just like your body.

There are four metabolic pathways for energy production:  aerobic liposis, aerobic glycosis, anaerobic glycosis, and ATP-CP. Depending on your demand for energy, your metabolism will select one or two metabolic pathways.

When your body is looking for ATP, it can derive it from different complex chemical processes (pathways).  The first and most basic of these is aerobic liposis.  (Liposis>lipid>”fat”).  Your metabolism finds free fatty acids circulating in your blood, combines it with oxygen, and can convert it into energy. This process, however, is complicated and time-consuming, and will not suffice when the body has a high energy demand.  Hence, aerobic liposis is used during non-exercise (that is, day-to-day life and activities), and very low intensity exercise (your heart rate can be elevated only a little bit).

The next pathway is aerobic glycocsis.  (Glycosis>glycogen>glucose>”sugar”).  Glycogen is sugar stored in your muscles and a few of your organs, and the average person can store about 1,500-2,000 calories of glycogen.  Glycogen is combined with oxygen to derive ATP.  You can think of glycogen as your fuel; and your muscles and organs, as your fuel tank. When exercising, your body depletes this fuel.  After exercising, you must eat (carbohydrates) to re-fill the tank.

The third pathway, anaerobic glycosis, generates ATP without the use of oxygen.  You can imagine red-lining your car, ripping through your fuel reserves, and smelling something hot and dirty from your vehicle’s effort.  The amount of glycogen needed for this effort is significantly higher, but because oxygen cannot be utilized, you get a nasty, burning by-product called lactic acid.  Lactic acid is what makes exercise burn; the effort from this kind of exercise can significantly wear down muscle tissue (this is not necessarily a bad thing).  At home, you’re exhausted, your body is humming, and you are hungry.  This “afterburn” from exercise is when weight loss and body re-composition happy. Your body scrambles around, looking for something to convert into glycogen (whatever carbohydrates you eat), and also goes around building and re-arranging proteins, to make your lean tissues bigger and stronger–more prepared, in case it ever has to do that exercise again!

The final pathway, ATP-CP, provides the most explosive energy to your body.  ATP stands for adenosine tri-phosphate. CP stands for creatine phosphagen. Basically, when that third leaf on the clover pops (ATP turns into ADP), the body goes immediately to rob that “P” from CP, to rebuild ADP to ATP.  Unfortunately, the body has extremely limited amounts of CP.  Energy from this system is provided for seconds only.

So, how can you train these systems?

Aerobic glycosis is any sustainable activity lasting anywhere from 20-90 minutes.  Even longer, if you are a seasoned endurance athlete. This system is trained by exercise like running, rowing, swimming, or general bodyweight and resistance exercises with high repetitions.

Anaerobic glycosis is a much less sustainable activity, that can last minutes only.  This can be anything from strength training (8,10, 12 repetitions) to intervals, to Fartlek training, Tabata intervals, to sprinting, to jumping.  Each effort is full tilt,and recovery time between efforts is ample.

The ATP-CP system provides energy for merely seconds.  Explosive and full-body recruitment exercises train this system.  Examples include some plyometrics, max-out lifting, 10 second sprints/intervals, throwing, etc.

**Note: seldom is the body ever exclusively in one pathway or another.  In fact, the body has a tendency to blend them.  For example, at rest, the body taps into its aerobic lipolitic (fat burning system), but might rely on the aerobic glycolitic system for up to 30% of its energy needs as well.  A multi-step full out effort, such as a Turkish get-up, might switch between ATP-CP and anaerobic glycosis.  Endurance lifting will certainly spread over aerobic and anaerobic glycosis.

Each system can be trained and adapted.  The more endurance activities you do, for example, the more you will be able to do later.  By keeping your body on a bobble between aerobic and anaerobic intensities, you eventually condition your body to accept more work (hence, you become more fit).

How?  One way is by increasing the number of mitochondria in your muscles.  Mitochondria are basically the “lungs” of your cells, and accept more oxygen.  The more oxygen your muscles can accept, the more energy they can deliver towards an effort.  This is one reason why it is important not to do the same exercise all the time, as your body becomes more and more efficient.  To make gains in fitness, you must always seek new ways to challenge yourself.

To be continued…

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by demogirl06 on July 12, 2010  •  Permalink
Posted in Exercise Physiology
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Posted by demogirl06 on July 12, 2010

http://mariamaestevens.com/2010/07/12/training-your-metabolic-pathways-part-1/

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