With thousands of people jumping on the rapid-weight-loss bandwagon, there are an increasing number of questions about whether crash dieting is really an effective way to lose weight.
While weight loss web sites, fitness gurus and magazine articles all claim to have the solution that will help you shed unwanted pounds in record time, it is clear to most fitness experts that these popular and widely touted techniques – such as juice diets, fasting, or weight loss supplements – do not provide lasting results.
To understand why, some knowledge of the way the body reacts to a reduction in the number of calories being consumed is necessary.
Your body stores energy in two different ways – as fat, and as glycogen, or blood sugar. Glycogen is the main source of fuel for the body; it is broken down from carbohydrates in the diet, and then stored attached to water molecules until it is needed.
When you first start dieting, by reducing the number of calories you consume each day, your body automatically turns to its stores of glycogen for the fuel it needs to function at its normal level. When glycogen is converted to energy, the water molecules used for storing it are excreted. This elimination of water accounts for the initial loss of body weight you experience.
Once its glycogen stores are depleted, your body then turns to energy stored in muscle tissue – your lean body mass. It is only after these other, more readily available energy sources are used up that your body finally begins to burn its fat stores. Since it can take at least two weeks of dieting to begin using fat for fuel, the initial weight loss phase of any diet includes only water and lean muscle mass.
How does this come into play with rapid weight loss programs?
Most short-term, rapid weight loss diets are designed to last no more than a week or two. Because the programs typically involve a drastic reduction in calories, sometimes completely eliminating entire food groups, it is unhealthy to continue to follow them for any longer than this. Since the body needs at least two weeks to start using up fat, it is clear that, while you may lose some of your overall body weight, you are only getting rid of water and lean muscle tissue.
Once you resume eating normally, however, you run into another problem. Dramatically cutting back on the calories you consume forces your body into a “starvation” mode, where it slows your metabolism in order to conserve as much energy as possible.
Even when your diet returns to normal, your metabolism remains in this conservation phase, storing as much fuel as it can; this is a survival mechanism that evolved to allow us to survive periods of time when little food was available, and your body is unable to distinguish between a voluntary calorie reduction and a famine.
The result is that once normal eating resumes, you quickly put back on the weight you lost, often gaining even more as your body struggles to adapt to the changes you have put it through.
So how can I lose weight and keep it off?
When we talk about losing weight, what most of us really have in mind is losing fat. Unfortunately, there are no shortcuts or easy solutions; in order to achieve lasting weight loss success, you need to change the way you think about dieting. In order to get rid of fat, first of all, you need to use more calories than you consume.
The best way to do this is to adapt your lifestyle to include a healthy diet and a regular exercise routine. There are plenty of resources available that can help you determine how many calories your body needs each day, which foods provide the nutrients you need to stay healthy, and which types of exercise are most appropriate for you.