We may have found the answer for why it is so hard for the beginners to lose body fat. And we know how to solve this problem!
A recent study in our lab (Human Countermeasures Laboratory at Texas A&M University) revealed that participants with less percent body fat increased more fat-burning protein, PPAR-delta, after performing just a single bout of whole-body resistance exercise. Furthermore, no matter how much your body fat percentage is, PPAR-delta content increases after 10 weeks of resistance exercise training. PPAR-delta encourages skeletal muscle to burn stored fat as fuel. It can be greatly beneficial to health because it decreases triglyceride (a form of fat) and LDL-cholesterol (aka bad cholesterol) levels and increases insulin sensitivity and HDL-cholesterol (aka good cholesterol) levels. Since exercise is associated with energy expenditure and PPAR-delta is related to energy production, it is no surprise that our body can naturally produce more PPAR-delta in skeletal muscle simply by doing exercise.
It has been well established that endurance exercise, such as running, may increase PPAR-delta content. During the recent decade, researchers started to focus on the effects of resistance exercise on aerobic capacity and notice that PPAR-delta may play an important role in the regulation of energy expenditure of resistance exercise. In our labs, we have revealed that resistance exercise training may increase PPAR-delta contents in rats. Our recent study further investigates the effects of resistance exercise on PPAR-delta in humans.
Fifteen untrained men and women were recruited to perform a 10-week progressive whole-body resistance exercise training program. We compared the PPAR-delta content on the different stage of exercise.
By comparing the amount of PPAR-delta content in the muscle sample before and after a bout of resistance exercise, we found that PPAR-delta content increased in inverse proportion to participants' body fat percentage. That is, participants with less percent body fat showed more increases in PPAR-delta content after performing only one bout of resistance exercise. This is an interesting finding because it shows that the leaner you are, the more fat your body tends to burn.
By comparing the amount of PPAR-delta content before and after the 10-week training program, we found that PPAR-delta content increased after 10 weeks of resistance exercise training. This result tells us that resistance exercise training may increase the body's ability to use fat as energy source, just like endurance training.
Therefore, for the beginners who are frustrated for the slow adaptation, you can blame the higher percent body fat. To solve this problem, simply keep going and the association between high percent body fat and blunted adaptation will be gone after several weeks of training.
1. Chen VCW, Lee CW, Bui S, Riechman SE. (2016). Skeletal Muscle PPAR-delta Increases Acutely with Resistance Exercise Inversely Proportional to Body Fat Percentage. FASEB J, 30:lb708
2. Chen VCW, Lee CW, Bui S, Lee TV, Fluckey JD, Riechman SE. (2014). Skeletal Muscle PPAR-delta increases with 10 Weeks of Resistance Training. FASEB J. 28:lb819
3. Barish, G. D., Narkar, V. A., & Evans, R. M. (2006). PPARδ: a dagger in the heart of the metabolic syndrome. The Journal of Clinical Investigation , 116, 590-597.
4. Brunmair, B., Brunmair, K., Dörig, J., Szöcs, Z., Stadlbauer, K., Marian, V., et al. (2006). Activation of PPAR-δ in isolated rat skeletal muscle switches fuel preference from glucose to fatty acids.Diabetologia , 49, 2713–2722.
This article was originally published in the Sydney & J.L. Huffines Institute for Sports Medicine & Human Performance website (2016)