The Reality Behind Metabolism Myths

So can we really change our metabolism or are we predestined to having a slugging metabolism? Can we blame our metabolism for our body weight? Does our age, gender, or race play a role in the number of calories we can eat?

Myth No. 1 - We can precisely calculate what our calorie needs are based on our metabolism.

A person's basal metabolic rate is the amount of energy required to sustain basic processes required for life. With today's technological advances, a person's oxygen consumption and carbon dioxide production can be accurately measured and used to calculate a one's basal or resting metabolic rate. Basal metabolic rate only accounts for about 70 percent of total energy expenditure. A person's actual energy expenditure is more complex and dependent on a number of factors - namely thermogenesis (the process of digestion, ingestion, absorption of food and regulation of body temperature), and physical activity. Physical activity includes all movement - not just exercise. Since physical activity or energy expenditure is dynamically changing component of life, it is difficult to really calculate a person's exact energy or caloric needs.

Energy Expenditure = basal metabolic rate + thermogenesis + physical activity

Myth No. 2 - Age, gender, and race don't effect basal metabolic rate.

All three play a role in metabolism. As humans age, the metabolic rate slows about 1 to 2 percent every decade after age 20. Also, because of their greater amount of muscle and larger organs, men have higher basal metabolic rates than women. And several studies indicate that metabolic rate differences exist between races and/ or ethnicities. Researchers are working to determine why African American females have slower metabolic rates than white females.

Myth No. 3 - So if we held our physical activity and caloric intake constant, we wouldn't gain any weight? And if weight gain occurs, then calorie restriction is effective?

Unfortunately, it is not that easy. Although physical activity and calorie intake are major variables in the energy expenditure equation, other factors play a role. First, it is important to understand that small changes in either variable over a short time will have little or no effect. You see, our body is so efficient that if we decrease our food intake for a week or two without increasing our physical activity, our metabolic rate slows to compensate for our calorie deficient. In times of famine, this attribute is helpful but when weight loss is the goal, it can be stifling. Humans are much more efficient at storing fat than burning fat. For this reason, it is imperative to stop weight gain before it occurs. The body was built to protect against famine rather than fighting weight gain. In addition, shifts in hormone levels can alter satiation (the feeling of fullness after a meal) or metabolic rate. For instance, when the thyroid gland releases insufficient thyroxine hormone, the basal metabolic rate slows causing weight gain. In addition, two obesity-related hormones leptin and ghrelin appear to affect weight. Researchers report a leptin resistance and an overproduction of ghrelin in obese people. Research continues to find answers to such hormonal problems.

Myth No. 4 - So if we overindulge one day, the only way to alter the energy equation is to exercise more?

Physical activity includes may aspects of life. Occupation is a key factor. A job requiring standing or constant motion provides much more energy expenditure than a sedentary desk job. Research indicates that people who fidget burn more calories. So to combat the battle of the bulge, make changes in every day routines. Take the stairs instead of the elevator. Park in the back of the lot and walk further. Walk around the house while talking on the phone. Also, bouts of exercise in increments of 10 minutes is equivalent to a 30 minute session. So, stop making excuses and go hit the pavement! And three or four times a week add an additional 10, 20 or 30 minutes of intense physical exercise.

In addition to getting enough physical activity, another key component is sleep. In recent years, sleep deprivation has been increasingly linked to obesity. Experts believe that not getting enough shut eye can cause alterations in glucose metabolism leading to insulin resistance, an increase in appetite, and a decrease in energy expenditure. Try for eight a night - to help the weight fight!

Myth No. 5 - The caloric intake portion of the energy equation tends to be the most variable on a daily basis. So to be sure not to overindulge, just eat low-fat foods? Right?

There are a lot of good reasons to cut your fat intake. Saturated fat and trans fat can cause cause heart disease. And fat has more than twice as many calories per ounce as carbohydrates and protein.

But you still have to reduce your overall caloric intake if you want to lose weight. Gorging on low-fat snacks won't make you slim. The best advice: Eat a well-balanced portion-controlled diet including lots of fruits and vegetables. Include carbohydrate, protein, and a small amount of healthy fat in each meal or snack for energy throughout the day. Drink water or low-calorie beverages. Limit sugary, high-fat items.

Myth No. 6 - To get a true fix on your weight, it's important to weigh yourself daily.

Losing a pound doesn't mean you've lost a pound of fat. Many circumstances can affect the magic number that appears on your bathroom scale. Some quick-loss diets impose a diuretic-type response; most of the weight lost is just water. But it is important to keep your weight in check but not obsess over every little change in body weight. Therefore, experts recommend weighing in twice a week and acting on the number if it continues to climb. For example, it your weight starts creeping upward, take action. Decrease your food intake and increase your physical activity.

Lessons learned: Energy expenditure is influenced by several direct and indirect variables - most important, food consumption and combustion. Although it is difficult to precisely calculate an individual's total energy expenditure, a estimation can be calculated. The most important issue is to be sure to keep the equation in balance to ensure weight gain does not occur. For once the weight gained, the thrifty human body makes it difficult to lose.

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