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Not only is she thinner than you, her muscles work better, too: Role of muscle function in maintaining weight

Date:
March 20, 2014
Source:
American Physiological Society
Summary:
Researchers examined how muscle physiology effects leanness. They found that while rats with 'lean genes' burned a similar amount of calories at rest as those with 'obese genes,' the muscles of lean rats burned much more energy during mild activity. The research sheds new light on the role of muscle function and metabolism in maintaining weight.
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FULL STORY

We all know the type: The friend or colleague who stays slim and trim without much effort and despite eating the same high-calorie fare that causes everyone else to gain weight. As it turns out, the way the muscles of the inherently thin work may give them the edge.

Daily physical activity is an inherited trait with a strong association to how fat or thin a person is. Chaitanya K. Gavini et al. previously found that aerobic capacity is a major predictor of daily physical activity level among humans and laboratory animals. In their new study, they compared female rats with high aerobic capacity (genetic tendency toward leanness) or low aerobic capacity (genetic tendency toward obesity) to investigate how muscle physiology affects leanness.

Though the rats in each group were similar in weight and lean body mass, the rats with a high aerobic capacity were consistently more active than the low capacity rats. While all the rats had similar energy expenditures when at rest, big differences in energy expenditure (calorie burn) occurred during mild exercise. The researchers found the muscles of rats with lean genes demonstrated "poor fuel economy," meaning that they burned more calories when performing the same exercise as those with fat genes. This may be due to more lean rats having higher levels of proteins that support energy expenditure and lower levels of proteins that encourage energy conservation and/or an increased sympathetic nervous system role in powering the muscles of lean rats.

According to the researchers: "This has implications for how we consider metabolism when attempting to prevent or treat obesity. Targeting of pathways maximizing skeletal muscle energy use during physical activity may take advantage of already existing mechanisms that are endogenously employed to a greater extent in naturally lean people."

The article "Leanness and heightened nonresting energy expenditure: role of skeletal muscle activity thermogenesis" is published in the March 2014 issue of the American Journal of Physiology -- Endocrinology and Metabolism.


Story Source:

The above post is reprinted from materials provided by American Physiological Society. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. K. Gavini, S. Mukherjee, C. Shukla, S. L. Britton, L. G. Koch, H. Shi, C. M. Novak. Leanness and heightened nonresting energy expenditure: role of skeletal muscle activity thermogenesis. AJP: Endocrinology and Metabolism, 2014; 306 (6): E635 DOI: 10.1152/ajpendo.00555.2013

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American Physiological Society. "Not only is she thinner than you, her muscles work better, too: Role of muscle function in maintaining weight." ScienceDaily. ScienceDaily, 20 March 2014. <www.sciencedaily.com/releases/2014/03/140320173416.htm>.
American Physiological Society. (2014, March 20). Not only is she thinner than you, her muscles work better, too: Role of muscle function in maintaining weight. ScienceDaily. Retrieved August 27, 2015 from www.sciencedaily.com/releases/2014/03/140320173416.htm
American Physiological Society. "Not only is she thinner than you, her muscles work better, too: Role of muscle function in maintaining weight." ScienceDaily. www.sciencedaily.com/releases/2014/03/140320173416.htm (accessed August 27, 2015).

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