Last night my foster son picked my brain regarding diabetes (his birth father is a Type 2 diabetic). While the entire car-ride conversation was ripe fodder for a blog post, what I’m going to recount here is our discussion on fatty liver, fructose, and diabetes.

What is fatty liver?

Fatty liver is an excess buildup of fat cells in your liver. When the liver becomes too fatty, inflammation occurs and liver function is compromised.

What does fatty liver have to do with diabetes?

They both are diseases of sugar metabolism. In Type 2 diabetes, your cells are insulin-resistant – they no longer respond to insulin’s attempts to pull sugar out of your bloodstream. In development of fatty liver, chronic high intake of fructose causes fatty deposits to develop in the liver.

Fructose?

Fructose is a type of sugar found in fruit (and in high fructose corn syrup, but we’ll get to this later). Chemically, it’s a simple sugar just like glucose but is metabolized differently. Glucose (and other sugars) are metabolized like this (courtesy University of Miami):

Fructose, however, follows a much shorter route:

Fructose—->Liver—->Fatty Acids

Ok, I’m dramatically oversimplifying the fructose pathway, but I want you to understand the “big picture” concept here. What happens with excess consumption of all carbohydrates is that they get repackaged as fat through a process called de novo lipogenesis.   However, there’s a limit to how much and how quickly sugar gets repackaged as fat – a rate-limiting step.

An analogy:  Imagine a FedEx shipping plant with a huge fleet of trucks and piles and piles of boxes to be shipped.  How quickly can you ship the packages?  The number of workers packing the trucks would be your rate-limiting step.  The boxes can only be delivered as quickly as the trucks are filled.  It doesn’t matter how large a fleet you have to deliver boxes with, without workers to pack them, the packages can only drip-drip-drip out of the plant.

The rate of sugar metabolism (see above complicated diagram) is bottlenecked by the regulatory enzyme phosphofructokinase.  Consume a ton of glucose, and what will eventually happen is that insulin rates rise, causing levels of leptin to rise, which limits your appetite.  No appetite = you stop flooding the system with sugar (but not before the damage is done).

Not so with fructose.  Fructose, that lucky dog, gets to skip that step.  Instead of having to be shuttled via the insulin pathway, fructose directly enters the liver and gets metabolized without this rate-limiting step.  So if you consume a lot of excess fructose, your liver synthesizes a lot of triglyceride (fat).  In fact, there’s practically no limit since insulin isn’t involved and thus your appetite won’t be blunted (recent research indicates that fructose effectively “shuts off” your appetite regulation).  So what happens?  Fatty deposits begin to show up in the liver (undelivered “packages” sitting around in the plant warehouse) – and over time, inflammation and liver cell damage occurs.  Continue this over time, and you’ve got the fertile breeding grounds for obesity and diabetes.

So does that mean if I eat fruit I’ll get diabetes?

It’s unlikely.  Remember, we’re talking about excess consumption of fructose.  Eat a bunch of fresh fruit, and you’re likely to consume 15-20 grams of fructose, tops.  But with industrialization of food and the addition of high fructose corn syrup as the primary sweetener used in food manufacturing, daily intake of fructose is nearly 4 times higher.  Think about all the possible sources of fructose – it’s in just about every sweetened drink you can think of: soda; fruit juices, iced tea, etc.  Moreover, sucrose (table sugar) is 50% fructose.  All that adds up to a considerable intake.

What it boils down to is that it’s easy to develop fatty liver (and diabetes) if you’re indiscriminate about what you eat and drink.  Avoid sweetened drinks high in high fructose corn syrup, stay away from sugar, and you’ll likely be fine.

Let’s offer a Cliffs Notes version of the above:

This great diagram from the American Liver Foundation (via msnbc.com) says it all:

As a general rule, sugar is bad for you.  But fructose is particularly bad.  So disregard what the food companies tell you and stay away.

The problem with being a know-it-all is that other people assume (not surprisingly) that you know it all.  Then, when a particularly bright (and well-researched) client says something like this:

I think modulation of the GLUT4 transporter is probably the key to the whole insulin sensitivity issue post exercise.  What do you think?

…you can only shrug your shoulders and say, “Gee, Gary, I don’t know…but I’ll get back to you on that.”

Have no idea what he was talking about?  Me either – until an hour ago.

What the heck is GLUT4 and why were we talking about it in the first place (read: killing time before the last exercise)?

First, some background.  You might recall me discussing the mechanism of insulin resistance, but here’s a quick catch-up:

Insulin functions to pull glucose (sugar) out of the bloodstream and into cells to be burned for energy or stored as glycogen (or to be stored as fat, if glycogen stores are already full).  Chronic high levels of insulin (caused by chronic high sugar intake) cause cells to become less responsive to insulin’s actions; in other words, cells stop responding to insulin and it becomes increasingly difficult to pull sugar out of the bloodstream and into the cells.  You body tries to compensate for this by increasing the amount of insulin (effectively “forcefeeding” sugar into the cells), but over time this strong-arming tactic grows less and less effective.  This process of insulin resistance eventually escalates into Type 2 Diabetes.

Conversely, being insulin sensitive is a good thing.  That means that it doesn’t require a whole mess of insulin to pull sugar out of your bloodstream.  Insulin sensitivity is strongly associated with longevity, which means you live longer if you’re more insulin sensitive.  Sounds good to me.

Ok, background established.  Now we’re about to wade into some deeper waters.  Tally ho!

Back to GLUT4:  GLUT4 is a sugar transporter protein that acts to “open the doors” for glucose (sugar) to enter cells.  There are 12 other sugar transport proteins, but the fourth isoform (GLUT4) is the main actor in glucose transport.

Let’s look at the insulin pathway a little more deeply here (thanks Wikipedia for a metabolic pathway diagram that isn’t intimidatingly offputting):

This diagram illustrates simply and clearly the process of glucose entering a cell.  Insulin binds to its receptor site and sets off a chemical cascade that activates GLUT4.  GLUT4 opens the doors, and glucose is allowed into the cell, where it meets one of three fates: Glycogenesis, glycolysis, or lipogenesis.

Straightforward and neat.  But there’s an exception: The post-workout period.

The post -workout period is special, because during this time, you’re as insulin sensitive as you can get (makes sense, since your body is attempting to replenish its fuel stores as quickly as possible during this period, let’s let as much glucose through the doors as is possible; fill ‘er up!).  Here’s a nifty fact:  The exaggerated insulin sensitivity occurs via GLUT4, and doesn’t require the action of insulin.  What this means is that you’re literally bulletproof (sugarproof?) in the post-workout period, until glycogen stores are full (all fuel tanks have been replenished.  After that point, even a little spurt of insulin is enough to shift you towards fat storage; since, where else are you going to store all this extra sugar?

So let’s distill that into Cliffs Notes:

You exercise, intensely.  By doing so you deplete muscle and liver glycogen (stored sugar), burning it for energy.  After exercise, you decide to eat a 5 pound bag of potatoes.  The starch in the potatoes gets broken down into its constituent parts, namely glucose – sugar.  GLUT4 opens the doors to your cells and the sugar flows in, refilling muscle and liver cells with glycogen.  At the same time, your insulin levels rise, since the goal is to get that glucose into the cells as fast as possible.  Insulin rises, more GLUT4 is activated, more doors are opened, and soon enough your glycogen stores are full.  All that leftover sugar?  Repackaged as fat.

This clarifies post-workout reuptake for me a lot.  And, it answers a question I’d had for some time:

Insulin spikes retard growth hormone release.  Growth hormone is required for synthesis of new (and repair of damaged) muscle tissue.  And yet, a mix of carbs and protein (not just any carbs either, but readily digestible – simple – carbs) seems to work best in both replenishing muscle glycogen and in stimulating muscle tissue synthesis.  What gives?

Now I know what gives – GLUT4 allows for glucose influx independent of insulin.  So I guess you’re right, Gary.

Every once in awhile (ok, well; often) a client will pass along a news story that’s so far off the mark that it makes me go Super Saiyan.  Here’s the latest one:

Cereal and Milk is the New Sports Supplement, Says Study.

Briefly, the new study looked at using a whole foods source – in this case, skim milk and Wheaties – to replenish muscle glycogen vs. a sport drink (probably Gatorade – the full study is available here).  The end result?  Milk and cereal worked just as well to replenish muscle glcoygen and even better at promoting protein synthesis than the sports drink.  In other words, Wheaties builds more muscle and refuels your muscles just as well as Gatorade (!).  So we should all be having a bowl of Wheaties after our workouts, then; right?

Yeah, not so much.

Let’s break this down in a science-y way:

We know from years and years of research that ingestion of carbohydrates post-workout speeds refueling of muscles by supplying muscles with the very fuel they need – glycogen (sugar).  Both the Gatorade and the Wheaties contain carbohydrate; hence they both work well to replenish muscle glycogen stores.  No mystery there.

Now the issue of protein synthesis (read: building muscle): We know from Jeff Volek’s research that ingestion of carbohydrate alone actually retards protein synthesis – it results in a net negative nitrogen balance – while a combination of protein and carbs accelerates protein synthesis.  Cereal and milk contains some protein along with copious amounts of carbohydrate; hence it worked to build muscle better than the Gatorade.  Mystery solved.

I applaud Dr. Kammer’s efforts to promote eating real foods as opposed to food supplements.  Where the problem lies is in making the mental leap in saying that you should have cereal and milk as your post-workout nutrition.  Yeah, it contains (scant) protein – but what about all that carbohydrate?  Why not, say, eggs and fruit?  Or chicken and a sweet potato?  Or a post-workout shake a la John Berardi with 2 parts carbohydrate to each 1 part protein?  Why skim milk and Wheaties?

Oh, because the study was sponsored by General Mills.

Why does this ruffle my feathers so?

1. News outlets consistently misreport the latest food findings.  They either distort the findings to make them more newsworthy (creating an unnecessary confusing maze of nutrition for the layperson) or flat out get it wrong.

2. It’s dreadfully difficult to get most people to eat enough protein.  If they aren’t worried about the purported (false) health risks of consuming meat, they (incorrectly) think that eating a salad with one chicken breast  is “enough protein.”  By the way, please don’t be this person.

Here’s an alternative: Tell people to eat a mix of protein and carbohydrates after exercise (and how much).  They’re smart; they can figure things out on their own.

Often I’m asked why I disagree that fat loss is “merely a game of calories in vs. calories out” and maintain that it’s a function of hormonal tone.  Gary Taubes makes an interesting analogy:

If you owned a restaurant and hired me as a consultant to help you figure out why business is down, and I came back and told you, “Oh, it’s because you have fewer people going into your restaurant than going out of your restaurant”, you’d probably slug me.  Of course you’ve got fewer people going in than coming out; that’s not the point.  The question you need to look at is:  Why?

Why indeed.  What’s implied by the statement “you’re fat because you eat too many calories” is that it’s all your fault, you dreadful pig.  There are starving children in rural China; how dare you.  I would argue that they are compelled to eat by virtue of what they eat.

Now this isn’t to absolve the overweight of personal responsibility.  ‘Tis true, no one held a gun to your head and forced you to eat all the wrong things.  But what it does do is to help you identify what those wrong things are, so you can stop eating them.

When you raise insulin levels (particularly easy to do if you overconsume refined carbohydrates), you do two things:

1.  You shift your cells from energy utilization to energy storage.  In other words, you turn on the ‘fat storage’ switch.

2.  You increase hunger.  There’s a reason “Betcha can’t eat just one” is the slogan for Lay’s Potato Chips and not Land O’ Lakes Butter.

Here’s an intellectual exercise:

Get together 8000 Calories’ worth of sweet potatoes, avocados, chicken, eggs, and leafy greens. Put it in a big pile in front of you, set a timer to 24 hours, and make that pile disappear before the timer goes off.  Good luck.

Now, put 8000 Calories’ worth of soda, pasta, pizza, and chips in front of you.  Set timer to 24 hours.  Go to town.  Again, best of luck.

I don’t think you’ll disagree with me that completing the task in scenario two (carbs) is far, far, far, far more feasible than completing scenario one.  But you don’t need to take it from me.  Just ask Michael Phelps how he managed to keep his dietary intake at 8000-10000 Calories/day while training for the Beijing Olympics:

I’m eating a lot of pasta and pizza. I’m eating a lot of carbs.

To repeat:  Eating carbs makes you store fat.  And it makes you hungry.

</end rant>

In Part 1 of this mini-series, I proposed that creating an algorithm can help you minimize confusion and help you to wade through the muck of needlessly complex training systems out there.  I proposed a general method of cataloging “valid” exercise systems based on emphasis on strength, progression, and recovery.  Part of why it’s difficult to generate specific questions on training systems is because the

Not so with nutrition.  The science isn’t crystal clear, but it certainly points you in a specific direction.  And so, instead of the general principles of the previous post, here is an algorithm for sound nutrition (arranged in 5 easy questions, for your convenience):

1) Does my diet emphasize real food? ‘Real food’ is easy to recognize but surprisingly difficult to describe.  It’s minimally processed.  It probably was alive at some point.  And chances are (although this isn’t always the case) a little light cooking is all the ‘processing’ you need in order to eat it.  A quick and dirty rule: If it comes in a box or brightly colored wrapper, it probably isn’t real food.  You could take every supplement available and still not obtain the complete spectrum of nutrition contained in whole foods (such as enzymes and yet to be discovered phytonutrients).  At the risk of sounding like a naive naturalist, it’s hard to improve upon what Mother Nature has already provided for us.

2) Does my diet deliver enough protein for my needs? There’s a great deal of needless controversy regarding what the optimal amount of protein you should eat in a day.  Despite what some authorities would tell you, there’s no danger of damaging your kidneys by eating too much protein, unless you’re diabetic and have already sustained kidney damage (and new research shows that this may not even be the case).  On the flip side, there seems to be no overt benefit in overconsuming protein either.  So let’s shoot down the middle with this one and say that if you’re exercising, then you should shoot for 0.7 to 1 gram of protein per pound of bodyweight (see the work of Jeff Volek and Peter Lemon for the hard science on this).

3) Does my diet limit grain consumption? Aside from being a concentrated source of carbohydrates (see #4), grain consumption is associated with a whole host of health problems.  By far the best reference on this is Loren Cordain’s exhaustive review of cereal grains (PDF file, opens in new window).  The Reader’s Digest version:  Grains inhibit nutrient absorption because they contain antinutrients, such as plant lectins and phytic acid.  They also are highly inflammation-causing.

4) Does my diet limit insulin? What’s the biggest factor in determining whether or not you’re burning fat?  Your insulin levels.  Chronic high levels of insulin (as in, say, someone who overconsumes carbohydrate) flip the metabolic switch in your cells from energy utilization to energy storage.  In other words, high insulin = what you eat is stored as fat.  And the converse is true as well – low insulin = more fat oxidation (read: fat burning) is taking place.  Not to mention that chronic high levels of insulin are associated with all sorts of unsavory disease processes, like high blood pressure and heart disease.  What can you do to prevent high insulin levels?  Minimize your intake of foods that significantly raise insulin – namely, carbohydrates.  The obvious ones:  Sugar, soda, bagels; and the non-obvious ones: Whole wheat bread, brown rice, tortillas.

5) Can I eat this? Let’s make one point clear: If you don’t like it, you ain’t gonna eat it.  My foster daughter doesn’t like pork and in the event of a zombie apocalypse she would rather starve to death than munch on Wilbur leftovers.  No matter how many times I harp upon the necessity of bioavailable vitamin B12, my sempai Andrius won’t be splitting a Ruth’s Chris porterhouse with me (he’s a vegetarian).  Simply put, to make dietary choices work for you, you’ve got to choose things you like (or can learn to enjoy).  The caveat:  If all you like are Jolly Ranchers and Fruit By The Foot, then change is a-gonna have to come to you.

Today’s New England Journal of Medicine had a special surprise for anyone interested in diet composition and weight loss.  By now, you’ve undoubtedly read or heard one of the headlines:

Want To Lose Weight?  Just Eat Less.

It’s Not What You Eat, It’s How Much.

Stick To a Low-Cal Diet and It Will Work. (This was my personal favorite.  What an awful headline.)

You’d be forgiven for thinking that this newest study proved, once and for all, weight loss ultimately comes down to calories in – calories out.  But it contains some glaring errors that skew the results, and you savvy readers out there will probably be able to identify them right away (particularly if you read the full text of the study – get it while you can!).

Here’s a summary of the study: 811 overweight adults were assigned to one of four diets: low-carb, low-fat, high-fat, and high-protein.  They were offered group and individual instruction in the diets and followed for two years.  The researchers measured weight loss and waist circumference.

The main problem I have with the study design – the nutritional breakdown of the diets:

* Low-fat, average-protein diet made up of 20 percent fat, 15 percent protein and 65 percent carbohydrates.
* Low-fat, high-protein diet of 20 percent fat, 25 percent protein and 55 percent carbohydrates.
* High-fat, average-protein plan containing 40 percent fat, 15 percent protein and 45 percent carbohydrates.
* High-fat, high-protein diet of 40 percent fat, 25 percent protein and 35 percent carbohydrates.

You can see where they went wrong here – based on the data in the study, none of the diets contain any less than 140 grams of carbohydrates (the so-called “low-carb” group).  And if you’re a regular reader of this blog or a low-carb aficionado, you know that 140 grams of carb intake is anything but “low-carb.”  At intakes of greater than 60-80 grams of carbs daily, you really don’t get much of the benefits of a low carb diet (insulin levels still trend too high).  But to achieve those levels of carb intake, the percentages would have to be much more heavily skewed towards fat – which, for researchers touting the current nutritional status quo – is a big NO-NO.

Consider this quote from the study:

Other goals for all groups were that the diets should include 8% or less of saturated fat, at least 20 g of dietary fiber per day, and 150 mg or less of cholesterol per 1000 kcal.

At 215 mg of cholesterol, I guess eggs are out (since at 1600 calories your daily limit is 240 mg of cholesterol).  You know, cholesterol and heart disease?  No connection. Saturated fat and heart disease?  No connection.  Someone should tell these guys.

No doubt low-fat experts like Dr. Joel Fuhrman will argue that his diet (at a whopping 10% of calories from fat) is grossly misrepresented as well and as such didn’t get a fair shake.  While I generally disagree with his diet conclusions, on this point, he’d be right.

Taking a cursory look at the composition of the different diets reveals that…well, they’re not all that different.  The Supplementary Appendix shows a listing of sample menus that the study participants were encouraged to follow.  Now, you tell me; does this look like a “low-carb diet” to you?

Breakfast:  Boiled or poached egg, whole wheat bagel w/lowfat cream cheese, cup of skim milk

Lunch: Turkey, whole wheat spaghetti, vegetable medley, one small banana

Dinner: Roast beef, one potato, mixed vegetables, cabbage salad w/walnuts, tiny box of raisins

Snack: Cup of skim milk and a graham cracker

If you’re eating bagels and crackers, let’s face it; you’re not eating a low-carb diet.  But before you take my rantings as a complete dismissal of all scientific inquiry, let me qualify everything and say I understand it’s not their fault.  The researchers are operating under incorrect premises (i.e., too much fat and cholesterol is bad for you) and as such are limited by that – the whole “Do No Harm” thing.  Think of it this way:  If they thought vegetables were toxic at a dose of greater than 500 calories per day, then they’d be ethically bound to limit the groups to 500 calories’ worth of vegetables (that might make for even more awkward study design).

But that’s enough quibbling.  Let’s take a look at some of the interesting data:

• As per usual, the groups had a tough time sticking to their respective programs but did better than most study participants.  They ended up with an average weight loss of 4kg (about 9 lbs).
• The lowest carb group increased their HDL level to a greater extent than other groups; the highest-carb group fared worst.
• “All the diets except the one with the highest carbohydrate content decreased fasting serum insulin levels by 6 to 12%; the decrease was larger with the high-protein diet than with the average-protein diet.”  This means that the greater you reduce carb intake, the greater the improvement in insulin sensitivity – and we all know that’s a good thing.
• An interesting finding:  The two groups that saw the least “improvement” in LDL levels were the highest-fat and the lowest-carb group.  This is probably due to an increase in the “large, fluffy” LDL particles and not the compact LDL (prone to oxidation).  If that was over your head, read this – or, just take my word that the smaller, more compact LDL particles are what predispose you to heart disease.

The last word:  The baseline data shows that virtually all participants were eating in excess of 2000 calories and 225 grams of carbs per day – yikes.  Reducing calories from 2000 to 1600 is going to make a positive impact health-wise when weight is lost.  And I’m not saying that reducing calories (independent of diet content) won’t result in weight loss – it will.  But a well-intentioned but poorly-designed study like this one does nothing but muddy the issue.  Sustaining insulin sensitivity is important.  Controlling blood sugar and hormonal tone (so you don’t get hungry; so fat-burning occurs as opposed to fat-storing) is important.  And you can do both those things better on a true low-carb diet than on a low-fat diet.

Edit (2/27/09):  Jeff points out that “both the “high protein” and “low carbohydrate” groups had favorable changes in waist size compared to the “low protein” and “high carbohydrate” groups respectively.”  Meaning, those groups probably lost more fat (as opposed to merely “weight”) than the higher carb groups.  Nice pick-up.

…in almost every single case.

Take this picture from Regina Wilshire’s blog, for instance:

While corn isn’t the best of all possible choices for you (it is a cereal grain, after all), you can easily see how eating the actual foodstuff is far, far better than its synthetic counterpart (that’d be high fructose corn syrup).

Corn growers would have you believe that high fructose corn syrup isn’t bad for you.  In fact, “it’s made from corn, has the same calories as sugar, and it’s fine in moderation.”

Well, that would be great if:

1. Corn were “good” for you in the first place (being a cereal grain, it’s not).
2. Sugar were “good” for you in the first place (it’s not).
3. Eating things in moderation were “good” for you in the first place (would they say eating lead paint chips was fine “in moderation”?).

All this skirts the issue of whether or not high fructose corn syrup is worse for you than sugar – and it is (I’ll go through the specifics in a detailed post later).  It has more to do with the metabolic effects of high fructose corn syrup (effects on hormonal tone, proteins, and the liver) than mere calories.

Jonny Bowden gives some sage advice: When shopping for food at your local supermarket, stick to the perimeter (where the meat and produce are) and avoid the center (where all the processed and manufactured items are).

First off, I’d like to apologize for my spotty postings as of late.  Post-summer is usually a busy season for personal training but I’ve found the demand this year to be (literally) almost overwhelming.  Please bear with me as I play catch-up.

In the meantime, here’s a list of things off the top of my head:

In preparation for the upcoming Pan Ams, the Gracies asked (ok, insisted) that I cut weight to 122 lbs (the cutoff for the lightest weight class, GALO) .  On a mildly related note, a recent University of Wisconsin-Madison study showed that photographic food diaries (in other words, taking a snapshot of what you eat before you eat it) was more effective for encouraging diet retention than traditional written food journals.  Since I easily lost 3 pounds over the course of this past week through small alterations of diet alone, my astute wife pointed out that I should keep an online photographic food journal for instructive purposes.  Looks like I’ll have to start carrying a camera along with me.

One fundamental point that continues to resurface time and time again is that “real food” is best for you, both in terms of health and aesthetics (read: your waistline).  And nothing highlights the profound differences between “real food” and “fake food” than seeing this photo (and accompanying post) about a McDonald’s hamburger from 1996.

Lastly, but not leastly: To Michele and Michael Hogan, I finally did a bonafide one-armed pullup (roughly 15 minutes ago at my brother-in-law’s birthday party).  I know, I know; video or it didn’t happen.  Hey, I have a roomfull of witnesses…

Today, as I trained my clients, not one session went by without talk about The Diet.

Yes, Michael Phelps‘ diet. I’ll refrain from passing judgment and try to talk about it from an athlete’s POV, as I feel news articles are sensationalizing Phelps – “What a freak.”

The question. “How can he eat all that and still look like this?”

The skinny bastard.

First, the info:

Now, the play by play:

Phelps is 6′4″, 195 lbs. He’s an Olympic-level athlete engaged in roughly 5 hours of rigorous swim training, as well as strength training. And he’s 23.

Using the Harris-Benedict Equation, we get a daily expenditure of 3971 Calories. Shows how limited prediction equations are.

Calculating Phelps’ BMR (Basal Metabolic Rate), we get 2089.65 Calories (per day). Add in the estimated expenditure from swimming and strength training (5100) and we come up with an estimated total of 7189.65 Calories per day.

That’s impressive, but it’s still not 8000-10000 Calories. So where do the extra thousand or so Calories go?

The X factors:

Lean mass – The prediction equations I used do not account for Phelps’ lean mass (read: muscle) which burns calories all on its own. You could argue that this accounts for an extra couple hundred Calories per day.

Thermogenesis – Not insignificantly, the food Phelps eats requires energy in order to be broken down and digested. Thermogenesis is estimated to contribute as much as 10% to metabolic rate. If Phelps really is downing 8000-10000 Calories a day, then his digestive system is working overtime to process that food. This could also throw a few hundred Calories into the mix.

Age – Phelps is young (and insulin sensitive). Metabolic rate slows as we age; conversely, we can expect metabolic rate to be higher in younger folks. Being insulin-sensitive helps drive those ingested calories to muscle cells (for use as energy) rather than to fat cells (to be stored for future use). So the food Phelps eats is used immediately (whereas ’tis not so in your average American Olympics viewer).

Reality – The realistic scenario is that Phelps isn’t really eating 8000 Calories everyday, and if we use food logs of athletes as evidence, this bears out. It’s possible that he eats 8000-10000 in a single day occasionally, but that his actual daily intake averages out somewhat lower (say, 6000 Calories or so). So, perhaps, one day he has 5500 Calories; the next 9798 Calories; the next, 6211 Calories, etc.

A final note: Some clients expressed shock and horror at the thought of an Olympic athlete eating pizza and pasta (especially after being told to avoid grains, etc.). My response: Phelps would not be physically capable of downing 8000-10000 Calories a day without the hunger-attenuating qualities of the carbs to aid him. It is precisely because he eats refined carbohydrates that he is able to put away that many calories.

Here’s an experiment: Get together 8000 Calories’ worth of sweet potatoes, avocados, chicken, eggs, and leafy greens. Put it in a big pile in front of you, set a timer to 24 hours, and make that pile disappear before the timer goes off.

Ready, set, go! Good luck.

(Actually, the timer should probably be set to 16-18 hours, since I’m sure Phelps sleeps a little.)

The moral? Phelps definitely expends tremendous amounts of energy daily, so much so that if he doesn’t eat an obscene volume of food, he actually loses weight. And in order to maintain that intake level, he resorts to eating from some admittedly crappy energy sources. Ironically, those same crappy foods enable him to eat the volume of food he requires.

O harmonious universe, how you taunt us!

Not to worry, all. Check back with Mr. Phelps in about 20 years or so – I suspect his caloric intake will be much different.

A client of mine asked me about his blood sugar yesterday and it occurred to me that writing an overview of blood sugar is in order (since I rant so about keeping insulin levels low, avoiding concentrated sources of carbohydrates, etc.).

First, what’s normal blood sugar?

The normal range for a fasted state is between 80 to 120 mL/dl. After eating, blood sugar generally jumps a little higher but not much, although if you load yourself up with sugar it can and will skyrocket (as much as 200 mL/dl). If you’re normal (i.e., non-insulin resistant), your blood sugar level is probably less than 100 mL/dl and will not rise past 140 mL/dl after a meal.

100 mL/dl is the “standard” that most general practitioners use, but diabetes specialists will ring alarms if your fasting blood sugar values exceed 83 mL/dl.

Why does blood sugar matter?

If you’re a regular reader of this blog, you already know the answer to this question. Having high fasting blood sugar levels shows insulin resistance, and insulin resistance is the first step down a road you definitely don’t want to take.

A recap:

All (not just the bad ones, but all) of the carbohydrate you consume gets broken down into glucose – the building block of carbs. When all goes well, glucose is absorbed from your bloodstream into your cells to be burned as energy. Insulin is the hormone that makes this absorption possible – it literally “opens the door” to your cells, allowing glucose in.

When all is not well (i.e., when you overconsume carbohydrates, particularly refined carbs), you end up with large amounts of glucose in your bloodstream. Normally, the body deals with glucose by secreting (more than) enough insulin to pull all of that sugar out of your bloodstream and into your cells to be used as energy or to be stored as glycogen. When you run out of glycogen storage space, your body simply repackages that glucose as triglycerides and socks it away in your fat cells.

Fat gain may be inconvenient, but it’s not the main issue here. The problem is insulin resistance – when cells grow immune to insulin’s effects and insulin can no longer ferry glucose into the cells. Chronic hyperinsulimia – high levels of insulin in the blood – is the root cause.

In short:

High blood sugar -> High Insulin -> Insulin Resistance -> Diabetes (and other diseases of civilization)

Sounds terrible. What can I do to prevent these insulin spikes?

The simplest way is to curb your dietary intake of carbohydrates. In other words, minimize consumption of grains, sugars, and starches.

If you do choose to consume carbohydrates, eat the “best” kinds: High in fiber and least refined (e.g., whole wheat pasta, brown rice, etc.).  As always, “real foods” are best.

Get the majority of your calories from meats, non-starchy (aka leafy) vegetables, low-sugar fruit, nuts, and seeds. Beans and legumes are ok; they’re high in fiber and relatively high in nutrients, but they also contain phytic acid, which can block absorption of nutrients.

Exercise helps by making your cells more insulin sensitive – in other words, exercise improves the ability of insulin to pull glucose into the cells.  So do it.

The $1000000 question: So if I eat mostly carbohydrates, I’ll get fat and die prematurely?

Ah, I knew you were going to ask me that eventually.  The answer is, it depends.  If you’re like my friend Andrius and the carbohydrates you eat are leafy greens, fruit, legumes, and low-GI starches and grains (e.g., sweet potato, quinoa, etc.), then probably not.  But if you’re like the average American or Australian and the carbs you prefer are soda, white bread, fried potatoes, or anything that comes in a box, then the answer is “likely.”

If you like short and easy to remember admonitions, here’s what this post boils down to:

Avoid refined starches, grains, and sugars.