I have a confession….

I like to read physiology research for fun.

Yes, it is totally true.

The good part is that I will help translate the research for you, so sit back and join me a journey of some cool fat burning physiology, especially regarding insulin and exercise.

The goal here today is to shed some light on how you can ramp up your fat burning to a high level.

Glucose Use

As we exercise our body becomes better at handling glucose. This is a great thing since glucose (sugar) is actually toxic in the bloodstream in high amounts. The body secretes insulin to get it the heck out of the blood and into tissues where it is safely stored for later use (glycogen or converted to fat and stored there) or burned for fuel. With regular exercise, the body needs less insulin to get the same job done!

Analogy Time

Think of someone trying to enter a room. Glucose comes to the door but has no arms, so it gets its buddy insulin to knock on the tissue door to allow entry. In tissue that is working correctly (no pathologies), insulin knocks a few times and glucose moves on in–everyone is happy. In tissue that is now becoming less sensitive to insulin, glucose needs more and more insulin to create more and more knocks at the door since the tissue is going “deaf” to the knocks.

If this goes on for a long period of time, the poor pancreas (the organ that has to crank out insulin) may burn out and lead to type 2 diabetes.
It has been shown that endurance training improves insulin sensitivity (1), but few studies have looked at resistance exercise (strength training).

Background

18 healthy recreationally trained active students (the typical college dude since they are easy to get into studies). They were randomly split into and endurance training or resistance training group

Pre Training

OCTT (oral glucose tolerance test) was done.
Endurance group–a max exercise test to exhaustion on a bike with a metabolic cart
Resistance group-10 RM (rep max) was done

Study Design

Beverage with 1,000 kcal (200 g of maltodextrin and 50 g whey hydrolysate) was given within 1 hour post training–holy post training beverage batman!
An OGTT was done 6 hours after exercise.

Results

No changes in glucose tolerance after endurance training.
Acute resistance training can significantly lower blood glucose (area under the curve) as shown by an OGTT for up to 6 HOURS later, even after a crapload (technical term) of carbs and protein post training!
That is pretty cool that this effect stays around for that long and with that many grams of carbs and protein after training.

Application

Resistance training wins again! Even if you eat a lot post training, your body is better at moving that fuel rapidly out of your blood stream.
I wish they would have monitored strength levels and body composition, especially with that many grams of carbs and protein post training. I know there are some other great studies on nutrient timing, but more data is good!

Although insulin levels are interesting, I am more personally interested in strength/body composition changes. You would expect that as the body becomes more sensitive to glucose you would drop body fat. Score another point for lifting heavy stuff (resistance training).

While all studies are limited, this one is off an ORAL Glucose Tolerance Test (OGTT), and therefore absorption of that many carbs and protein in the gut may be an issue for some people in the study. Maybe they should have measured expired gases not just from the mouth!

If you can’t absorb it, you will have a different response vs. someone who can. Researchers will then get into a heated debate about the best way to measure insulin response, but of the other ways are more invasive (multiple sticks for an IV at times) and much more time intensive. Plus, if you want to compare it to the average gym rat (who believes that taking in any carbs will inhibit their fat burning), they will be using an oral drink so having an oral drink in the study is better for that comparison.

Summary

To modify glucose tolerance, resistance training appears to be better. Save those carbs for post training, hit some weight, and look forward to a leaner you!

Rock on
Mike N

References
1. Ivy J. L., T. W. Zderic, D. L. Fogt. Prevention and treatment of non-insulin-dependent diabetes mellitus. Exerc Sport Sci Rev. 27:1-35, 1999.
2. Venables M. C., C. S. Shaw, A. E. Jeukendrup, A. J. Wagenmakers. Effect of acute exercise on glucose tolerance following post-exercise feeding. Eur J Appl Physiol. 2007.