When you need to achieve dramatic weight loss in a short period of time, eating very little can seem like a good idea. But taking in very few calories on a daily basis can be dangerous to your health and likely won’t help you achieve successful or lasting weight loss. By choosing a healthy diet with the calories your body needs to power its daily functions, you can maintain a healthy body and weight.
How Low Is Too Low?
Your car wouldn’t run without fuel -- and neither can your body. That’s why women on very low-calorie diets (VLCDs) can experience a number of adverse health effects. Consuming low-calorie diets, such as eating only 900 calories per day, does not give your body the nutrients it needs to sustain physiological functions, according to Go Ask Alice!, a health resource from Columbia University. When you do not eat enough calories, your body goes into “starvation mode,” slowing your metabolism to conserve as much energy as possible. In this state, you may find you have difficulty losing weight because your body is trying not to burn the very few calories you take in.
A VLCD can contribute to a number of symptoms that affect your thinking and energy levels. For example, a low caloric intake is associated with poor concentration and cognitive development, according to Go Ask Alice! Your energy levels decrease and you may feel constantly fatigued and irritable. Your body relies on calories to power brain function, and low calorie intake affects your ability to think clearly, leading to poor work and school performance.
Low calorie intake can have severe and sometimes deadly symptoms. This includes loss of menstrual periods, or amenorrhea, and infertility. Your immune system cannot produce needed antibodies, which makes you more susceptible to colds and other illnesses. Your dental health can suffer and you can experience anemia and bone loss that increases your risk for bone breakage. Ultimately, a very low-calorie diet can be deadly because your heart, lungs and brain cannot function without energy.
Your daily calorie needs vary based on three criteria: how old you are, your gender and how active you are on a daily basis. The more active you are, the more calories you need because your body requires calories for energy. Inactive women between ages 19 and 30 need about 1,800 to 2,000 calories per day, while inactive women between 31 and 50 need about 1,800 calories, according to the National Institutes of Health. If you are somewhat active or perform light activities such as walking about 30 to 40 minutes per day, you need about 2,000 to 2,200 calories if you are 19 to 30 years old or 2,000 calories if you are 31 to 50 years old. If you hit the gym regularly or are active on a sports team or outdoors, you need about 2,400 calories per day if you are 19 to 30, or 2,200 if you are 31 to 50 years old.
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