Are all calories created equal?

Following on from the 'is the caloric equation a sham' blog I'm going to dig around a bit in the 'are all calories equal' nexus.

For the purposes of my investigation I'm going to compare the calories in two substances.  I'm going to compare the ingestion of 1 glass of orange juice and the caloric equivalent in oranges.  Here's the maths;

1 large (I'm a big chap - so it's large all the way for me) of McDonalds orange juice =

The equivalent calories in raw commercial oranges =3.5 oranges

[1 piece of fruit yields 86 grams of juice so I need 3.5 oranges to get the equivalency for the juice]

So, let us begin.  I have in front of me these things;

Let's start with the McDonald's orange juice.

I drink one of these in 2-3 minutes - sweet delicious nectar, presented cold, with a straw to aid my efforts. 

This stuff hits my stomach in just seconds, has no fibre or fat, and the significant 58 grams (10 teaspoons) of fructose are off to my liver for some processing within 30 minutes.  There, my liver processes it and if I don't need any glycogen, it's likely fat city.  Fructose is not the best of sugars as it has no glucose tracking system.  They say we evolved in almost a 'fructose free' environment.  More on the trouble sugar brings us all another day.

So, what do I have so far.  No nutrient value other than a bang of vitamin C (about 50% of daily allowance) a whallop of fructose to trouble my liver (remember, the liver has a fixed capacity so the same way you don't want to abuse it with alcohol you don't really want to trouble it with large doses of fructose either) and all this in short time frames (that's what happens when you strip out the fibre).  The quick digestion of this causes a spike in two things.  One is vitamin C (expensive urine coming as this a water soluble vitamin) and the other is insulin (in response to the blood sugar).

So, for the calories I get a thermonuclear explosion of a hormone which seems to be the root cause of many long term issues (syndrome X, diabetes) and expensive pee.

I move on to my three oranges. 

I eat three oranges, let's say in 6 mins (2 minutes each to peel and quaff).  By the time I eat the third I'm feeling kind of full and sweet enough to be honest.  But I push through.

What's making me feel full.  Well the 12 grams of fibre for one thing (54% of my RDI in one sitting by the way).  Why am I getting sweet overload - it's the mouth.  Sweet is a huge sensation across the mouth (which is why we have sweet and sour - sweet will tame almost any other taste) and these orange segments explode and broaden the flavour hit.  Not so with the orange juice squirted half way down my mouth with the straw and even if I drank it normally most of the sweet quickly passes across the tongue and away.

The fibre also slows the digestion down a lot.  1-2 hours later I'm getting a steady stream of fructose, a small insulin response and a stead supply of vitamin C, vitamin A, calcium (all that pulp fibre has some extra love in it), and a smidgen of iron for my efforts.

Okay, so all I've done so far is establish that calories don't come in the same packages - nature's packaging is the best.  But what is really happening here with how my body is responding to the calories. 

Firstly, the likelihood of storing fat is directly associated to insulin levels.  Insulin is the mac daddy of hormones (working on a hormonal axis with glucagon) designed to get energy stored - all energy.  So, when insulin spikes you get glycogen being stored and fat being stored.  Perfect sense in our evolutionary past, but a real nightmare in our abundant present.  So, if you drink juice (58 grams at a time) you better be ready for belly fat.  If you eat the equivalent calories in oranges, you needn't be as concerned.  Even though the calorie content is the same, my body is reacting differently because of how the calories are digested - one a roller coaster ride with a fat landing, the other a steady as she goes buzz with no conceivable detriment.

Secondly, research in to diabetes has shown that maintaining low insulin levels has both a direct impact on morbidity (read, living with a sad face) and mortality.  The lower your insulin is consistently (i.e. keeping it in a low range) the better your chances of more life.  All sugars in nature are packaged naturally with fibre (be it seeds, husks, pulp, any form of cellulose really) - you just can't find free sugars floating around fluid (honey is about as close as you'd get but you'd need to be rather game to go after that).  So, eat fruit and you'll be okay despite the calories.  The fat is available for burning (because inslulin says low), the sweet tooth is satisfied, the satiety lasts (whole fruit is significantly better at delaying the desire to eat again than juice) and you get a bunch of bonuses all along for the ride.

Oh, and you save your bowel some trouble too.  That indigestible fibre.  That's going through and keeping your colon (less cancer) healthy too!

To summarise;

All calories are not the same as

1. they do not cause the same hormonal response which directly effects what your body does with the calories ingested
2. they come packaged with better nutrition, satiety effects and nutrients whenever nature is involved.

The next question for a blog is; 'should we worry more about hormones than we do about exercise and nutrition'?