Surviving on 600 calories per day is not recommended for most people, as it is considered an extremely low-calorie diet (VLCD) that can be dangerous for your health. The average recommended daily caloric intake for a sedentary adult is around 2000-2500 calories, and even low-calorie diets typically do not go below 1200 calories per day.

Restricting calorie intake to such a low level can lead to several negative effects on the body, including:
- Malnutrition: Consuming only 600 calories per day is likely to result in malnutrition, as the body will not be receiving sufficient amounts of essential vitamins, minerals, and macronutrients (carbohydrates, proteins, and fats).
- Slowed metabolism: When the body is not receiving enough calories, it may slow down its metabolic rate to conserve energy, making it harder to lose weight.
- Loss of muscle mass: A VLCD can result in the loss of muscle mass, which can have negative effects on overall health and fitness.
- Weakness and fatigue: Consuming only 600 calories per day can result in weakness and fatigue, as the body does not have enough energy to perform basic functions.
- Dizziness and fainting: Extremely low calorie intake can lead to dizziness, lightheadedness, and even fainting, as the body struggles to maintain adequate blood sugar levels.
- Hormonal imbalances: VLCDs can lead to hormonal imbalances, including decreased levels of thyroid hormones and sex hormones.
In addition to these negative effects on the body, following a VLCD can also have negative effects on mental health, including increased stress and anxiety.
It is important to note that while a VLCD may result in rapid weight loss, this weight loss is often temporary and can be difficult to maintain in the long term. Restricting calorie intake to such a low level can also lead to a rebound effect, where the body quickly gains back the weight that was lost once normal eating habits are resumed.
In conclusion, surviving on 600 calories per day is not recommended for most people and can be dangerous for your health. If you are looking to lose weight, it is important to do so in a healthy and sustainable way, such as by following a balanced diet that includes plenty of fruits, vegetables, lean protein, and whole grains, while also engaging in regular physical activity. If you are considering a VLCD or any other drastic dietary change, it is important to consult with a healthcare professional first.