Posts Tagged ‘Metabolism’

-Excerpt from an article I read, thought I’d share…link below*

Picture a morbidly obese mouse, you know, the ones companies use to show as the “before” picture when marketing certain products.  Anyhow, let’s call him Jumbo. Jumbo is unique – he’s an ob/ob mouse. This is a mouse that becomes a type II diabetic, can’t stop eating, and packs away body fat like crazy. No matter how much you feed him, he won’t stop.
Poor Jumbo has a mutation in the gene coding for leptin – he’s totally missing it! His fat cells can’t properly communicate with his hypothalamus because he has no leptin. If you inject Jumbo with leptin, he’ll stop eating and lose weight, but the solution isn’t so simple for us non-mutants.  Most obese people don’t have missing or mutated leptin genes – they can make plenty of it. The problem is that in spite of leptin still finding and binding its receptors all over the body, no downstream message is sent. The system that senses leptin is broken.
This is called leptin resistance, a condition in which the brain can’t determine when body fat is at an okay level. The fat cells are sending leptin out to the hypothalamus to signal that fat stores are full. Leptin binds the receptors, but no downstream messages are sent. It’s like knocking on the door when nobody is home. In spite of all the extra body fat mass, the brain perceives starvation and orders fat storage. The kicker is that you’re also very hungry, and continue to eat more and more.
If you know anyone who just can’t stop eating like Jumbo, as tempting as it may be to instantly judge them, it’s likely not entirely their fault. Many obese people have metabolic systems that are simply broken. You can’t outrun Mother Nature, and if the leptin signaling is messed up, you can only control yourself so much.

 

For full article by John Meadows CSCS check out:  <http://www.t-nation.com/free_online_article/most_recent/control_leptin_and_control_your_leanness&cr=&gt;

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Human Energy Systems & Metabolism.

Macronutrient Energy Systems…

Energy can be derived from three major food sources, commonly referred to as Macronutrients- Proteins, Carbohydrates, and Fats (lipids). Energy can also be derived from Alcohol…as well as, increased estrogen levels in men coupled with elevated aromatization, specifically at androgen receptor sites, sclerosis of the liver, crazy fluctuation of Insulin levels, not to mention a cascade of catabolic processes that are set in motion. Generally (minus a couple rare extenuating circumstances), one gram of each of the three nutrients (plus Alcohol) yield the following calories:

1 gram of Protein = 4 calories
1 gram of Carbohydrates = 4 calories
1 gram of Fat = 9 calories
1 gram of Alcohol = 7 calories

For all intents and purposes, the calories in food represent a form of potential energy for our bodies to produce heat and to work. Knowing how many calories (i.e. energy) are in the foods consumed can reveal how much we need to perform the work inside our bodies as well as all our movements (e.g., Gain Weight). Conversely, if we eat less than we need, the body will draw on it’s stores for energy (i.e., lose fat/weight).

Human Energy Systems…

Our bodies must take the energy stored in foods (macronutrients) and transform it into an energy form our cells can use immediately and/or store for future use. Energy in the body is available for immediate use in the form of Adenosine Triphosphate (ATP). It is a complex molecule constructed with high-energy bonds which, when split by enzyme action, releases energy rapidly for a number of body processes including tissues in small amounts. Another related high-energy phosphate compound, phosphocreatine (CP), is also found in the tissues in small amounts. Although it cannot be used as an immediate source of energy, it can rapidly replenish ATP. ATP can be formed from protein, carbs, and fats.
Metabolism; Human metabolism represents all physical and chemical changes that take place in the body. Metabolism involves two fundamental processes: Anabolism and Catabolism. Anabolism is a building-up or constructive metabolism. Catabolism is the tearing-down process involving the disintegration of body compounds into their simpler components. The breakdown of muscle glycogen to glucose and eventually CO2, H20 and energy
is an example of a catabolic process. The energy released from some catabolic processes is used to support the energy of anabolism. Therefore, metabolism represents human energy. The metabolic rate reflects how rapidly the body uses it’s energy (calories) stores. Many factors affect this rate but none so much as lean body mass (LBM) and exercises.

Basal metabolism or Basal Metabolic Rate (BMR) represents the energy (calories) required for fundamental life functions at rest, not including digestion of food. Resting Metabolic Rate (RMR) is the BMR plus the additional energy expenditure needed to digest food. RMR is typically 5-10% higher than BMR. If we can estimate our RMR and add our daily activity energy needs, we arrive at an estimate of our daily total energy (calorie) requirements. This is our caloric maintenance level. In other words, our body fat or weight remains stable when consuming this amount of food. A favorable or unfavorable body composition change results from a disruption in a caloric maintenance or energy balance.