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June 2009: Calories and Weight Loss
While it is true that calories are the ultimate determinant of weight status, there are many factors involved in weight loss success. Over the next few months I will be addressing the many components of healthy weight loss to help you achieve your weight loss goals and ultimately the best you can be!! But before addressing these other factors lets begin with a little science lesson that explains what a calorie is and what it does.
A calorie is merely a measurement of energy expenditure. The word calorie is often used in place of the scientific term kilocalorie which is a measurement of the amount of energy needed to raise the temperature of one kilogram of water by one degree centigrade at sea level. I know it all sounds pretty scientific, boring and dry, but when thinking about calories just remember that calories are a unit of measurement - specifically a unit of energy - and that it is simply a way of describing how much energy your body could get from eating or drinking a specific food or beverage.
If you eat more calories than your body needs, the leftover calories are converted to, and stored as, fat. A pound of fat is equal to 3500 calories. So if you wanted to lose weight you would need to reduce the amount of daily calories that you take in to put your body in a state of “negative energy balance.” Simply put this means that you will need to take in less calories than your body expends to promote weight loss. Unfortunately some people mistakenly believe that they must burn off all the calories they eat to promote weight loss. Not only is this untrue, it can be unsafe as well. Your body needs ample calories just to carry out basic body functions such as breathing and keeping your heart beating. When we reduce our caloric intake to levels that are too low the body will begin breaking down lean muscle mass to fuel itself. It will also slow down metabolism as a means of conserving energy - a definite no no when it comes to successful weight loss! Typically metabolic rate begins to decrease after just a few days of beginning a very low calorie diet.
And besides putting your body at risk for nutritional deficiencies, irritability and fatigue, very low calorie diets (in essence the body's starvation response) put you at risk for additional weight gain once you return to your previous eating pattern, a phenomenon often referred to as “yo-yo dieting” or “weight-cycling.” This is why skipping meals and low calorie diets promising “quick” results” sabotage long term weight loss success. Quick weight loss may actually be obtained using these approaches, however the body will eventually adapt to the reduced calories it is receiving and begin to conserve energy by slowing down metabolism (the mechanism by which your body burns food for energy). The body's metabolism starts to become less efficient at managing food with each diet attempt and weight that has been lost begins to be put back on at a quicker rate due to the body's slowed metabolism, thus leading to increased weight gain and the yo-yo effect.
The key to achieving healthy weight loss involves slowly reducing calories (by no more than 500 calories/day) and tapping into the body's stored fat. Stored fat provides the energy the body needs to keep trucking along while preventing the metabolism from slowing down too much. It also helps prevent the loss of lean muscle mass that occurs during severe calorie restriction. And increasing your muscle mass (which leads to a faster burning metabolism) is a definite yes-yes when it comes to healthy weight loss!! So when embarking on a weight loss journey remember to gradually decrease caloric intake while increasing physical activity for the best results.
So rather than setting out on an all or nothing quick weight loss program, consider adopting a more sustainable - and sane - approach to weight loss. Modest weight loss (just five to ten percent of your current weight regardless of how much you weigh right now) can yield great health benefits! Many lifestyle related diseases such as diabetes, hypertension, and heart disease can be positively impacted with just a small weight decrease. Thinking of weight loss as more of a lifestyle change and less of a diet will greatly help you reach your goals!
And addressing lifestyle habits (including physical activity and the how(s), what(s), when(s) and why(s) you eat) can profoundly impact not only your weight but your overall health in a positive way.
Next month: Goal setting - Creating realistic goals is an excellent way to improve your weight loss mind set.