Although reducing your calorie intake can help slim your waistline, consuming too few calories can lead to unpleasant, even dangerous, side effects. In fact, very low-calorie diets don’t work any better than low-calorie diets long term, according to a study published in a 2006 edition of the journal “Obesity.” Avoid the dangers of insufficient calorie intake, including malnutrition, by eating at least 1,000 calories per day.
Very Low-Calorie Diets
When it comes to calories, eating less isn’t always better. Consuming 800 calories per day or less -- which is a very low-calorie diet -- is only safe under medical supervision, according to Weight-control Information Network. Obese women may benefit from a medically supervised very low-calorie diet if they have immediate obesity-related health risks. VLCDs often consist of nutrient-dense, meal-replacement health shakes. If a VLCD is right for you, your doctor can help you plan your diet. However, WIN reports that patients following VLCDs have an increased risk of developing gallstones.
Negative Side Effects
Eating too few calories on a regular basis can lead to malnutrition, which can negatively affect your mood and energy level. Weight-control Information Network reports that eating fewer than 800 calories per day can cause you to become constipated or have diarrhea, and can lead to nausea and fatigue. Some other unpleasant side effects, especially for women, are hair loss, lack of menstruation -- which can affect fertility -- and fainting, according to MedlinePlus.
Eating disorders are more common among women than men. According to South Carolina Department of Mental Health, about 7 million women, or 1 in 200 U.S. women, and 1 million men in the United States have anorexia. Anorexia is an eating disorder characterized by an insufficient calorie intake, underweight, a fear of gaining weight and a distorted body image. The same source reports that about 20 percent of anorexics die from complications related to their eating disorder. If you’re underweight and think you may have an eating disorder, talk with a doctor or dietitian to get treatment and move toward a healthier body weight.
Healthy Body Weights
To look and feel your best, aim to maintain a healthy body weight. According to a study published in a 2008 edition of “Environmental Health and Preventative Medicine,” women should maintain a body mass index, or BMI, of greater than 17.5 to help prevent malnutrition and the negative side effects associated with it. However, BMIs of 25 or higher are classified as overweight or obese. To calculate your BMI, multiply your body weight by 703, then divide by your height in inches; finally, divide by your height in inches once again. For example, a woman who is 5 feet 4 inches tall and weighs 120 pounds has a BMI of 20.6, which is within the healthy range.
Minimum Safe Intakes
Most women need 1,600 to 2,400 calories per day to maintain a healthy body weight, according to the Dietary Guidelines for Americans 2010. To lose weight while minimizing health risks and negative side effects, aim for at least 1,000 calories per day. The review published in a 2006 edition of the journal “Obesity” reports that diets containing 1,000 to 1,500 calories per day are just as effective long term as 800-calorie diets.
- Obesity: The Evolution of Very-Low-Calorie Diets: An Update and Meta-Analysis
- Weight-control Information Network: Very Low-Calorie Diet
- MedlinePlus: Malnutrition
- South Carolina Department of Mental Health: Eating Disorder Statistics
- Environmental Health and Preventative Medicine: Low lymphocyte Count in Underweight Japanese Women
- U.S. Department of Agriculture and U.S. Department of Health and Human Services: Dietary Guidelines for Americans 2010
Erin Coleman is a registered and licensed dietitian. She also holds a Bachelor of Science in dietetics and has extensive experience working as a health writer and health educator. Her articles are published on various health, nutrition and fitness websites.