While your goal may be to lose weight, your body still requires sufficient amounts of food and nutrients to function and be healthy. Therefore, any intake that is less than 1,000 calories daily is not recommended and could potentially be dangerous. It can cause weight loss too quickly, which is not sustainable. This can lead to rapid regaining of weight upon resuming a normal diet.
Additionally, you would likely develop nutritional deficiencies because you are not consuming enough daily to properly fuel your body. This can cause unwanted side effects due to inadequate intake of vitamins and minerals. Typically, a minimum of 1,200 calories per day is recommended (2).