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2 posts from September 2010

09/13/2010

Can we change our body shape

The general shape of an individual is defined mainly by that person’s inherited skeletal structure, muscles and fat. So is it possible to change our body shape or are we stuck with what we’ve been given?

Skeletal structure grows and changes up until adulthood and then remains essentially the same until death. Muscle mass and fat distribution develops during puberty due to the influence of hormones, but can also be affected by activity levels and diet. Muscle mass and fat distribution then continue to change throughout life, due to these same influences.

So the answer is yes, we can have an effect on our body shape; the easiest and simplest way being through diet and exercise.

Some things are of course harder to change than others. During puberty, men develop broad shoulders and expanded ribcages to support the oxygen requirements of a larger muscle mass while women experience a widening of the hip bones to accommodate childbirth. For hormonal reasons, women also store most of their body fat in their buttocks, hips and thighs while men store most of their body fat around the abdominal area.

Unfortunately it appears to be human nature to want the opposite of what we have, and so we have a growing number of body conscious men who want bigger legs to balance out their expanded chests and broader shoulders, and women who want more shapely arms to balance out their larger buttocks and thicker legs. And of course we all want to be lean, because leanness is associated with the youth and virility that we are all so desperately trying to gain and/or hang on to.

As body shape is affected by muscle and fat distribution, does it not follow that by manipulating our muscle and fat distribution we can change our body shape. This is essentially what bodybuilding is all about.

Diet and exercise controls the amount of body fat that we store on our bodies, so a healthy calorie controlled diet and active lifestyle gives us control over our jelly bellies and chunky thighs.

The type of diet and exercise we follow affects the size and distribution of our muscle mass, so a “tailor made” diet and training program gives us control over our chicken legs and stick arms.

Sound easy? Nothing worth working for is ever easy but the results are always worth the effort!

09/06/2010

Exercise Makes You Feel Full

There is now another good reason to exercise. Besides burning calories, exercise restores the sensitivity of neurons involved in the control of satiety (feeling full), which in turn contributes to reduced food intake and consequently weight loss.

This is the conclusion of a study led by Brazilian researchers at the University of Campinas, and the findings will be published next week in the online, open access journal PLoS Biology. This disclosure may bring hope to over 40% of the population that suffers from weight problems and obesity around the world.

The increase in obesity has become one of the most important clinical-epidemiological phenomena. Factors such as changing eating habits and a sedentary lifestyle both have a role in the pathogenesis of this disease. It is postulated that excessive consumption of fat creates failures in the signal transmitted by neurons controlling satiety in a region of the brain called the hypothalamus. These failures can lead to uncontrollable food intake and, consequently, obesity.

The group led by José Barreto C. Carvalheira demonstrated that exercising obese rodents showed signals of restored satiety in hypothalamic neurons and decreased food intake. "In obese animals, exercise increased IL-6 and IL-10 protein levels in the hypothalamus, and these molecules were crucial for increasing the sensitivity of the most important hormones, insulin and leptin, which control appetite," Carvalheira explained.

Physical activity contributes to the prevention and treatment of obesity, not only by increasing energy expenditure but also by modulating the signals of satiety and reducing food intake.

Physical activity has always been considered a cornerstone in the treatment of obesity, however, only now have the effects of exercise on the control of body weight been understood. Thus, these findings, besides reinforcing the necessity for regular exercise also change the current paradigm established between physical activity and weight loss.

Funding: This study was supported by grants from Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) and Conselho Nacional de desenvolvimento científico e tecnológico (CNPq).