|Resistance training alone won't make up for a sloppy diet - no matter if you do it before or after meals.|
Abnormally elevated postprandial glucose and triacylglycerol (TAG) concentrations are strong risk factors for cardiovascular disease (CVD) in patients with type-2 diabetes. Therefore, scientists expect that interventions that reduce postprandial glucose and TAG concentrations should lower the risk of CVD (Krook. 2003; O'Gorman. 2008).
Previous studies have shown that acute exercise typically lowers postprandial glucose and TAG concentrations (Tobin. 2008) in patients with type-2 diabetes, but as Timothy D. Heden et al. point out, there is considerable heterogeneity in the responses with some individuals not experiencing beneficial changes in these risk factors (Gill. 2007; van Dijk. 2012).
"One potential explanation why some patients with type-2 diabetes do not have beneficial changes in postprandial glucose and TAG with acute exercise is because of the timing of the acute exercise session relative to meal consumption. Limited evidence suggests that the timing of aerobic exercise around a meal may be important and might explain why some individuals are exercise “insensitive” or “non responders”." (Heden. 2014)The only study to directly compare the effect of pre-meal and post-meal aerobic exercise on postprandial glucose concentrations in patients with type-2 diabetes showed that post-dinner, but not pre-dinner walking, lowered postprandial glucose concentrations (Colberg. 2009).
|Figure 1: Previous studies indicate that aerobic workouts after meals have more beneficial effects on the potentially unhealthy increases in glucose or triglycerides (Collberg. 2009)|
The question that remained was: Is the same true for resistance training?
Since resistance exercise (RE) has a more pronounced long(er)-lasting effect on ones metabolism than aerobic training, the researchers from the University of Missouri tested the hypothesis that post-dinner RE, compared to pre-dinner RE, would in fact be more effective at improving two clinically important postprandial risk factors (glucose and 109 TAG) for CVD at a time of day when they are typically highest in obese patients with type-2 diabetes.
The standardized test workout consisted of the following exercises (in this order): leg press, seated calf raises, seated chest flyes, seated back flyes, back extensions, shoulder raises, leg curls, and abdominal crunches. All exercises were performed for three sets (1-2 min rest between sets) of 10-repetitions for each RE. During this session, the first set for each exercise was a warm-up set and the weight used was 50% of the participants 10-RM. After the warm-up set, the weight for the next two sets was the participants previously determined 10-RM.
|Figure 2: Postrandial lipid response in the obese type II diabetics (Heden. 2014)|
Similar effects were observed for the insulin and glucose responses (see Figure 3) which were significantly improved and should thus complement the beneficial effects of the reduced triglyceride and very low density lipoprotein (VLDL) levels.
- Colberg, Sheri R., et al. "Postprandial walking is better for lowering the glycemic effect of dinner than pre-dinner exercise in type 2 diabetic individuals." Journal of the American Medical Directors Association 10.6 (2009): 394-397.
- Dalgaard, Marian, Claus Thomsen, and Kjeld Hermansen. "Effects of one single bout of low-intensity exercise on postprandial lipaemia in type 2 diabetic men." British Journal of Nutrition 92.03 (2004): 469-476.
- Gill, Jason MR, et al. "Effect of prior moderate exercise on postprandial metabolism in men with type 2 diabetes: heterogeneity of responses." Atherosclerosis 194.1 (2007): 134-143.
- Heden, Timothy D., et al. "Post-dinner resistance exercise improves postprandial risk factors more effectively than pre-dinner resistance exercise in patients with type 2 diabetes."
Journal of Applied Physiology (2014). Ahead of print.
- Krook, Anna, et al. "Reduction of risk factors following lifestyle modification programme in subjects with type 2 (non‐insulin dependent) diabetes mellitus." Clinical physiology and functional imaging 23.1 (2003): 21-30.
- O'Gorman, Donal J., and Anna Krook. "Exercise and the treatment of diabetes and obesity." Endocrinology and metabolism clinics of North America 37.4 (2008): 887-903.
- Tobin, L. W. L., Bente Kiens, and Henrik Galbo. "The effect of exercise on postprandial lipidemia in type 2 diabetic patients." European journal of applied physiology 102.3 (2008): 361-370.
- van Dijk, Jan-Willem, et al. "Exercise and 24-h glycemic control: equal effects for all type 2 diabetic patients?." Medicine and science in sports and exercise (2012).