The answer to the question of how many calories per day constitutes starving will differ depending on your sex, age, height, weight and activity level. Many experts consider diets of less than 800 calories per day to be very-low-calorie diets, according to the Weight-control Information Network. Very-low-calorie diets should be undertaken only with physician supervision.
Figuring Your Ideal Calorie Intake
Everyone has different daily caloric needs, so a starvation calorie intake will also vary. For a small, thin, inactive woman, 1,200 calories per day might be all she needs to maintain her weight; eating 1,500 calorie per day would result in weight gain. For a large, active man who needs 3,500 calories per day to maintain his weight, 1,500 calories per day -- a deficit of 2,000 calories -- would result in a weight loss of 4 pounds per week, a too-rapid weight loss by most diet experts' standards.
In some cases, very overweight individuals with major health problems related to obesity are put on very-low-calorie diets of 500 to 800 calories per day. Calorie intake this low requires close physician follow-up, plus frequent blood work to make sure you're getting the vitamins and minerals you need. At a calorie intake this low, you might feel weak, tired, irritable and unable to carry on your normal daily activities. People who undertake this type of diet lose around 44 pounds in 12 weeks, according to the Weight-control Information Network.
MayoClinic.com states that eating very few calories per day will put your body into starvation mode, a state in which your body tries to save itself from starvation by lowering your metabolism, thereby conserving calories. This decrease in metabolism is small, less than 5 percent, according to registered dietitian Dorene Robinson. Some dieters have taken the fact that dieting can lower your metabolism slightly and developed a theory that you need to eat more to lose weight if you're stuck in a diet plateau. There are no documented cases supporting the idea of needing to eat more to lose weight, according to Robinson. Dieters who don't lose on a restricted-calorie diet are likely under-reporting what they eat.
Starvation can have serious effects on every organ in your body, including your heart, liver and kidneys. At the most extreme, cardiac arrest and death can occur if you develop a severe electrolyte imbalance. Less drastic but potentially serious side effects include gallstones, weakness, hair loss, skin rashes, thinning or dry skin and diarrhea. You might also have difficulty thinking clearly. Your body temperature can drop and your susceptibility to infection increases.
A registered nurse with more than 25 years of experience in oncology, labor/delivery, neonatal intensive care, infertility and ophthalmology, Sharon Perkins has also coauthored and edited numerous health books for the Wiley "Dummies" series. Perkins also has extensive experience working in home health with medically fragile pediatric patients.