The idea of a low-calorie diet might tempt you because it seems like the quickest, surest way to lose weight. It certainly isn't easy, but it will get results. However, many negative side effects come along with restricting your calorie intake below 1,200. Some side effects are minor and will pass with a good meal, but some are more serious and can land you in the hospital. Do not attempt a low-calorie diet unless you are under the strict supervision of your doctor.
Calorie Needs Explained
Your body needs a certain amount of calories to carry out vital functions. If it does not get those calories from the diet, it can start to break down its own tissues for energy. To figure out how many calories you need per day, multiply your ideal weight by 12 if you are not very active or 15 if you are active, according to the University of Maryland Medical Center. To lose weight, aim to eat around 500 fewer calories per day than your body needs to maintain your weight. Eating less than that will lead to side effects.
Minor Side Effects
Eating less than 1,200 calories per day will send your body into starvation mode. Do not attempt this sort of diet without the supervision of a physician. Some side effects are minor in comparison to others and transitory. They can become more pronounced depending on how much you restrict your calories. Some symptoms of severe calorie restriction are weakness, fatigue, cold intolerance, irregular menstrual periods, dizziness, constipation and swelling of the hands and feet, according to "Nutrition, Exercise, and Behavior: An Integrated Approach to Weight Management."
Major Side Effects
Gallstones are caused by going on a severe calorie-restricted diet and losing weight too quickly. Often, you will need to have surgery to remove your gallbladder if this happens. Gout, or a painful inflammation of the joints caused by high uric acid in the blood, can start or become worse from low-calorie dieting. Since you are not taking in the proper amounts of vitamins, proteins and electrolytes, you are at risk for malnutrition disorders and electrolyte imbalances. Sudden death is a very rare but possible side effect from extremely low-calorie dieting.
Low-calorie diets force your body to take energy from other sources. You are more likely to burn muscle than fat because your body needs protein, according to Healthwise. This lowers your metabolic rate and makes it more difficult to lose weight. You are also not likely to stay on this type of eating plan for long, and you will eventually go back to your normal eating patterns. All the weight will come back. Furthermore, the electrolyte imbalances will cause your body to leach calcium from your bones, potentially weakening them and leading to osteoporosis.