Sugar and “Starches”
This is the big area of controversy, and of course, research.
Sugars (and “starches”) can be divided into 3 groups:
- monosaccharides like glucose, fructose, and galactose.
- disaccharides like sucrose (glucose-fructose) or HFCS (glucose-fructose) or lactose (glucose-galactose)
- Polysaccharides or “starches” like maltodextrin
You would think monosaccharides are the fastest for absorption, being a single molecule, but that is not the case. galactose is absorbed slower than a complex molecule like maltodextrin.
A 2:10 marathoner can burn up to 1200 kCal/hr (using a simple formula of 100 kCal per mile). There is no way you can ingest that many calories whether in solid form or liquid form to be metabolized as quick. You cannot metabolize calories and carbs into the blood, muscles and liver as fast as you burn them.
But your body is smart enough to replenish the glucose into energy as needed, and that path comes from different biochemical pathways, ranging from free glucose, muscular glycogen, liver glycogen and fatty acid oxidation (I should add gluconeogenesis as well for those who are doing long term fasting with glycogen reserves totally empty, but that’s being picky)
During intense exercise the only thing that will cause your blood glucose level to decrease is depleting your liver glycogen reserves.
So back to sugars in sports drinks.
Drinks with “sugar” will contain one or more from the following 3 groups above: monosaccharides, disaccharides , and Polysaccharides. I know when I make my custom protein drink (back in the days of The Protein Factory), I try to combine it with 3 types of protein based on digestibility, i.e. fast acting versus slow acting.
With different biochemical and metabolic pathways, if 1 is good, 2 is better, then 3 must be best?
Now to really confuse you: what combination is best? Glucose, fructose or a combination in the form of a disaccharide sucrose? HFCS? galactose? Polysaccharides like maltodextrin?
There are literally hundreds of journals and research papers out there. Here are 3 samples:
Comparison of fructose and glucose ingestion before and during endurance cycling to exhaustion (This study demonstrated that fructose and glucose are of equal value in prolonging ETE in endurance cycling Ingesting fructose before and during exercise apparently provided a more constant supply of glucose to be available to the working muscles)
Superior endurance performance with ingestion of multiple transportable carbohydrates (Ingestion of fructose+glucose led to an 8% improvement in cycling time-trial performance compared with ingestion of glucose)
The effect of galactose supplementation on endurance cycling performance (Ingestion of an 8% galactose-only solution (12.5 ml per kg body wt per h) is detrimental to endurance performance compared with equivalent volumes of iso-osmotic solutions containing 50% galactose/50% glucose or 80% glucose/20% fructose. This may reflect the inability of the liver to convert galactose into glucose at a rate required to support strenuous exercise intensity.)
So it all comes down in choosing the right combination of a multiple-sugar sports drink to enhance the performance in an endurance event.
Again, you want to focus on the different rates of absorption, so you might as well arm yourself with 3 different types of carbs.
Galactose had a bad rap based on a single study as the only source of energy, but I think it has a place in drinks using a combination for immediate and sustained energy. Galactose is mostly hydrolyzed from the disaccharide lactose, which is found in milk. (another reason why it’s a popular post recovery drink in the form of chocolate milk)
One brand that comes to mind, and that’s HYPR as it has the 3 different “sugars”. We don’t know the exact ratio, but we do know they exist in decreasing order based on their label, and that is a combination of maltodextrin, galactose, and fructose.
There’s isn’t one magic pill out there, but a combination of different ingredients makes sense, as long as you don’t have an allergy to these ingredients.
And finally, there is HFCS. Sucrose is 50:50 glucose:fructose, and HFCS comes in 3 different grades of fructose concentrations. As the mainstream media is putting a nail in the coffin for HFCS, expect to see it eliminated in sports drinks, or at least change the name to give it a new identity. Same Stuff, Different Day.
This is Part 3 of a 4 part series.
Part 1: Intro
Part 2: water & electrolytes (sodium, potassium, magnesium)
Part 3: sugars, starches and (heaven forbid) HFCS!
Part 4: protein, BCAA, glutamine, caffeine tyrosine, taurine, and other nootropics, creatine, others