Anytime you eat fewer calories than you take in you'll lose weight, barring any medical condition that inhibits weight loss. Eating too few calories in an effort to shed pounds isn't healthy, however, and it isn't the most effective way to weight loss. When you do that, your body goes into starvation mode to conserve energy, and you may find yourself experiencing a weight-loss plateau, not to mention health problems from not getting the nutrients your body needs. Always consult with your physician before dieting.
Starvation Mode Basics
Your body is equipped with its own starvation defense mechanism, which has evolved over millions of years to protect you during times when food was scarce -- a problem most people don't have today. When you take in too few calories to support activity and normal physiological functioning, your body adapts by reducing the amount of energy it uses to accomplish tasks. Your body may also turn to lean muscle mass for energy in order to conserve its valuable fat stores, just in case it doesn't receive more food anytime soon.
Starvation Mode's Effects on Weight Loss
Your body's adaptation causes your basal metabolic rate, which accounts for more than 60 percent of the calories your body burns daily, to slow down. This, in turn, causes you to burn fewer calories, even though you might be performing exactly the same tasks as when you were eating a regular diet. In addition, the gradual loss of muscle mass reduces your body's calorie-burning ability because the body uses more calories to maintain lean muscle mass than it does fat mass.
How Low Can You Go?
It's not clear what calorie intake level brings on starvation mode and whether the effects are increased the lower the calorie intake. In an article on the Waldo County General Hospital website, Dr. Kristie Leong writes that 1,200 calories per day is the absolute lowest level one should drop to when dieting. Otherwise, Leong says, the body will start to conserve fat, making weight loss more difficult.
In some instances, a very-low-calorie diet of fewer than 800 calories per day may be prescribed by a doctor if the patient has a significant amount of weight to lose. The diet, which consists of specially formulated liquid shakes and bars, is meant to kick-start weight loss for obese people who may experience complications, like high blood pressure, because of their excess weight. These diets must be undertaken only under medical supervision due to the dangers of consuming too few calories and losing weight rapidly. These include fatigue, constipation, nausea and diarrhea as well as more serious side effects like gallstones.
A Safer Way to Lose Weight
According to the Weight-Control Information Network, very-low-calorie diets, requiring medical supervision, generate the same amount of weight loss as low-calorie diets over the long term. Lose weight safely and effectively, by reducing your current calorie intake by 500 each day, which will lead to weight loss of 1 pound per week. Add an hour of exercise to your daily schedule to burn another 500 calories each day for a 2-pound-per-week sustainable weight loss.