If I Eat 800 Calories a Day for a Month, How much Weight Will I Lose? I’m 15, 5′1″ and currently Weigh 99 lbs.

If I eat 800 Calories a Day for a month, how much weight will I lose? I’m 15, 5′1″ and currently weigh 99 lbs.

Eating only 800 calories per day is considered extremely low and can have adverse effects on your health, especially for someone your age. It’s important to prioritize your well-being and consult a healthcare professional or a registered dietitian who can provide personalized advice for your specific situation.

WeekStarting Weight (lbs)Estimated Weight Loss (lbs)
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However, consuming only 800 calories per day is considered an extremely low calorie intake and may not be safe or suitable, especially for a teenager. It is crucial to consult a healthcare professional for personalized advice on healthy and safe weight management.

Losing weight depends on various factors, including your current weight, height, activity level, metabolism, and overall health. It’s important to approach weight loss in a healthy and sustainable way, especially as a teenager.

Eating only 800 calories a day is considered extremely low in terms of caloric intake. Generally, a healthy weight loss goal is to aim for a gradual and steady reduction of 1-2 pounds per week. To achieve this, it’s often recommended to create a calorie deficit of around 500-1,000 calories per day, depending on your individual needs.

However, as a teenager, your body is still developing and requires proper nutrition for growth and development. Severely restricting your caloric intake without professional guidance may not be suitable or safe for you. It’s crucial to consult with a healthcare professional, such as a registered dietitian or doctor, who can assess your individual circumstances and provide personalized advice.

Remember, sustainable weight loss is typically achieved through a combination of a balanced and nutritious diet, regular physical activity, and adopting healthy lifestyle habits. It’s important to prioritize your overall well-being rather than focusing solely on the number on the scale.

How much weight can I lose if I eat 800 calories a day for a month?

It’s important to note that weight loss is a complex process influenced by various factors, including individual metabolism, body composition, activity level, and overall health. Additionally, rapid weight loss can have negative health consequences and is generally not recommended without medical supervision.

That being said, consuming 800 calories a day is considered a very low-calorie diet (VLCD). Such diets are typically recommended for medically supervised weight loss programs for individuals with significant excess weight or obesity. VLCDs should only be followed under the guidance of a healthcare professional to ensure proper monitoring of health and nutrition.

The amount of weight you can lose in a month by consuming 800 calories a day will depend on your individual circumstances. Generally, a safe and sustainable rate of weight loss is considered to be around 1-2 pounds (0.5-1 kg) per week. Keep in mind that weight loss is not always linear, and your body’s response may vary.

If you’re considering making changes to your diet and lifestyle, it’s best to consult a healthcare professional or a registered dietitian who can provide personalized guidance based on your specific needs and goals. They can help you develop a safe and effective plan for weight loss while ensuring you meet your nutritional requirements.

How many pounds will I lose a week if I eat 800 calories a day?


Eating 800 calories a day is considered a very low-calorie diet (VLCD), and it’s important to note that this level of calorie restriction should only be undertaken under medical supervision. Rapid weight loss can have negative health consequences and is generally not recommended without proper monitoring.

Assuming you were to consume 800 calories a day, the amount of weight you could lose in a week would depend on various factors, including your individual metabolism, body composition, and overall health. As a general guideline, a safe and sustainable rate of weight loss is considered to be around 1-2 pounds (0.5-1 kg) per week.

It’s worth noting that weight loss is not always linear, and initial rapid weight loss on a VLCD may be due to factors such as water weight and glycogen depletion. As you continue on such a low-calorie diet, your body’s metabolism may slow down, making further weight loss more challenging.

It’s important to prioritize your health and well-being when considering weight loss. It’s generally recommended to work with a healthcare professional or a registered dietitian who can provide personalized guidance based on your specific needs and goals. They can help you develop a safe and sustainable plan that includes a balanced diet, regular physical activity, and appropriate monitoring.

What happens if you eat 800 calories a day for a month?

Eating only 800 calories a day for an extended period, such as a month, is considered a very low-calorie diet (VLCD). While VLCDs can lead to significant weight loss, it’s important to note that they should only be undertaken under medical supervision. Rapid weight loss can have negative health consequences and is generally not recommended without proper monitoring.

Here are some potential effects and considerations of following a VLCD:

  1. Weight loss: Consuming such a low amount of calories can result in weight loss. However, the rate of weight loss may vary depending on individual factors such as metabolism, body composition, and overall health.
  2. Nutrient deficiencies: Severely restricting calorie intake can make it challenging to meet your nutritional needs. A VLCD may not provide sufficient vitamins, minerals, and other essential nutrients, which can lead to deficiencies and potential health risks.
  3. Muscle loss: With a significant calorie deficit, your body may turn to muscle tissue as an energy source. This can result in muscle loss, which is undesirable as muscles play a crucial role in overall health and metabolism.
  4. Metabolic adaptations: Prolonged calorie restriction can cause your metabolism to slow down as your body tries to conserve energy. This can make further weight loss more difficult and lead to weight regain when you resume a regular calorie intake.
  5. Fatigue and low energy: Severely limiting calories can leave you feeling fatigued, weak, and lacking in energy. It may affect your ability to perform daily activities and exercise.
  6. Psychological impact: Following a highly restrictive diet can have psychological effects, including increased food cravings, feelings of deprivation, and an unhealthy relationship with food. It’s important to consider the mental and emotional aspects of dieting.

It’s crucial to prioritize your health and well-being. If you’re considering making significant changes to your diet, it’s best to consult a healthcare professional or a registered dietitian who can provide personalized guidance based on your specific needs and goals. They can help you develop a safe and sustainable plan for weight loss while ensuring you meet your nutritional requirements.

How many kg will I lose if I eat 800 calories a day?

The amount of weight you may lose by consuming 800 calories per day depends on various factors, including your current weight, body composition, metabolism, and activity level. However, it’s important to note that consuming such a low calorie intake for an extended period can have significant health implications and is generally not recommended without medical supervision.

To provide a rough estimate, one pound of body weight is approximately equivalent to 3,500 calories. This means that to lose one kilogram (2.2 pounds) of weight, you would need to create a calorie deficit of around 7,700 calories.

However, it’s crucial to prioritize sustainable and healthy weight loss methods that include a balanced diet, regular physical activity, and consultation with a healthcare professional or registered dietitian. They can provide personalized guidance based on your specific needs and goals.

What happens if I only eat 800 calories a day for a week?

Eating only 800 calories a day for a week can lead to rapid weight loss, but it is not recommended. It can cause nutritional deficiencies, muscle loss, slowed metabolism, fatigue, and other negative effects. Sustainable weight loss should involve a balanced diet, regular exercise, and consultation with a healthcare professional.

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Eating only 800 calories a day for an extended period can have several effects on your body and overall health. Here are some potential consequences:

  1. Nutritional deficiencies: Severely restricting your calorie intake can make it challenging to obtain all the essential nutrients your body needs. This can lead to deficiencies in vitamins, minerals, proteins, and fats, which are crucial for maintaining optimal health.
  2. Muscle loss: Consuming a very low calorie diet can cause your body to break down muscle tissue for energy. This can result in a loss of muscle mass, which is undesirable as muscles help support your metabolism and overall strength.
  3. Slowed metabolism: Consistently eating at such a low calorie level can cause your body to adapt by slowing down your metabolism. Your body may enter a state of energy conservation, making weight loss more difficult in the long run.
  4. Fatigue and weakness: Inadequate calorie intake can lead to feelings of fatigue, weakness, and low energy levels. Your body may struggle to meet its energy demands, making it challenging to carry out daily activities and exercise.
  5. Nutritional imbalances: Consuming only 800 calories a day may result in an imbalanced macronutrient distribution, with insufficient carbohydrates, proteins, and fats. Each of these macronutrients plays essential roles in supporting bodily functions.
  6. Negative psychological effects: Severely restricting calories can lead to feelings of deprivation, irritability, mood swings, and a preoccupation with food. It may also increase the risk of developing disordered eating patterns.

It’s crucial to prioritize your health and well-being when considering weight loss. It is generally recommended to follow a balanced and sustainable approach that includes regular physical activity, a varied and nutrient-dense diet, and consultation with a healthcare professional or registered dietitian who can provide personalized guidance based on your specific needs.

Can a person survive on 800 calories a day?

While it is possible for some individuals to survive on 800 calories a day for a short period, it is not recommended for long-term sustainability or overall health. Severely restricting calorie intake can lead to a range of negative effects, including nutritional deficiencies, muscle loss, weakened immune system, hormonal imbalances, and organ dysfunction.

The human body requires a certain amount of energy and nutrients to support its basic functions, including organ function, metabolism, and cellular processes. Consuming only 800 calories a day may not provide adequate energy or nutrients to sustain these functions properly.

If you are considering a calorie-restricted diet, it is important to do so under the guidance of a healthcare professional or registered dietitian who can ensure you are meeting your nutritional needs while still creating a safe and sustainable calorie deficit if weight loss is your goal. They can provide personalized advice based on your specific circumstances and health requirements.

How long can a human survive on 800 calories a day?


The length of time a person can survive on 800 calories a day varies depending on individual factors, such as body composition, metabolism, activity level, overall health, and nutrient status. However, it’s important to note that consuming such a low calorie intake for an extended period is not recommended and can have significant health implications.

In general, severely restricting calorie intake for an extended period can lead to malnutrition, muscle wasting, weakened immune system, organ dysfunction, and other serious health problems. The body requires a sufficient amount of calories and nutrients to support its basic functions and maintain overall health.

If you are considering a low-calorie diet, it is crucial to consult with a healthcare professional or registered dietitian who can provide personalized guidance based on your specific needs and goals. They can help you develop a safe and sustainable approach to achieve your desired outcomes while prioritizing your health and well-being.

Why am I not losing weight at 800 calories a day?

There are several reasons why you may not be losing weight at 800 calories a day. Possible causes include inaccurate calorie counting, metabolic adaptation, underlying medical conditions, plateau effect, inadequate exercise, and psychological factors. Consulting with a healthcare professional or registered dietitian can provide personalized guidance to address these factors and support weight loss efforts.


If you’re not losing weight despite consuming only 800 calories a day, several factors could be at play. Here are a few possible reasons:

  1. Inaccurate calorie counting: It’s important to ensure that you’re accurately tracking your calorie intake. Sometimes, people underestimate portion sizes or overlook hidden calories in condiments, oils, or beverages, which can lead to unintentional calorie consumption.
  2. Metabolic adaptation: Your body’s metabolism can adapt to lower calorie intake over time, slowing down to conserve energy. This can make weight loss more challenging. Additionally, severe calorie restriction can lead to muscle loss, which further reduces your metabolic rate.
  3. Underlying medical conditions: Certain medical conditions, such as hormonal imbalances (e.g., thyroid issues), insulin resistance, or polycystic ovary syndrome (PCOS), can affect weight loss. If you suspect an underlying medical condition, it’s important to consult with a healthcare professional for proper evaluation and guidance.
  4. Plateau effect: Weight loss often occurs in phases, and it’s common to experience periods of plateau where your weight remains stable for a while. This can happen due to various factors, including changes in water retention, muscle gain, or changes in body composition. Patience and persistence are key during these phases.
  5. Inadequate exercise or activity levels: While diet plays a crucial role in weight loss, incorporating regular physical activity and exercise can aid in burning calories and maintaining muscle mass. If you’re not incorporating exercise, adding it to your routine may help stimulate weight loss.
  6. Psychological factors: Stress, emotional eating, or other psychological factors can influence weight loss progress. It’s important to address these factors and develop healthy coping strategies to support your weight loss journey.

Remember, weight loss is a complex process influenced by multiple factors. It’s advisable to consult with a healthcare professional or registered dietitian who can assess your specific situation and provide personalized guidance to help you reach your weight loss goals in a safe and sustainable manner.

What happens to your body when you only eat 800 calories a day?

When you consistently eat only 800 calories a day, your body undergoes several changes and adaptations in response to the severe calorie restriction. Here are some effects that can occur:

  1. Weight loss: Consuming a significantly low calorie intake can lead to weight loss as your body is not receiving enough energy to meet its needs. However, the weight loss may come from a combination of fat, muscle, and water.
  2. Metabolic slowdown: Your body’s metabolism adjusts to the reduced calorie intake by slowing down to conserve energy. This can make weight loss more challenging as your body becomes more efficient at utilizing the limited calories.
  3. Muscle loss: Severely restricting calories can lead to muscle loss. Your body may break down muscle tissue for energy, particularly if you are not engaging in regular resistance exercise. Losing muscle mass can negatively impact your strength, metabolism, and overall body composition.
  4. Nutrient deficiencies: Consuming such a low calorie intake can make it difficult to obtain all the necessary nutrients for optimal health. This can result in deficiencies of essential vitamins, minerals, proteins, and fats, leading to potential health problems.
  5. Fatigue and low energy: Inadequate calorie intake can cause feelings of fatigue, weakness, and low energy levels. Your body may struggle to meet its energy demands, impacting your physical and mental performance.
  6. Hormonal changes: Severe calorie restriction can disrupt hormonal balance in your body. It can lead to changes in the levels of hormones involved in appetite regulation, metabolism, and reproductive functions.
  7. Nutritional imbalances: With limited calories, it may be challenging to achieve a balanced macronutrient distribution. Insufficient carbohydrates, proteins, and fats can affect various bodily functions and compromise overall health.
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It’s important to note that consuming only 800 calories a day is generally not recommended for prolonged periods without medical supervision. Such low-calorie diets can have significant health implications and are not sustainable or conducive to long-term weight management. If you are considering a calorie-restricted diet, it is crucial to consult with a healthcare professional or registered dietitian to ensure it is appropriate for your individual needs and goals.

Can you lose weight eating 800 calories 2 days a week?


Eating 800 calories for only two days a week, also known as intermittent fasting or a form of alternate day fasting, can potentially lead to weight loss. This approach, called the 5:2 diet, involves consuming a reduced calorie intake on two non-consecutive days and eating normally on the remaining five days of the week.

By reducing calorie intake for those two days, you create a calorie deficit, which can contribute to weight loss over time. However, it’s important to note that the weight loss may not be solely from fat but can also involve water weight and muscle loss.

While intermittent fasting approaches like the 5:2 diet can be effective for weight loss, they are not suitable for everyone. It’s important to consider individual factors such as overall health, specific dietary needs, and any underlying medical conditions. It is recommended to consult with a healthcare professional or registered dietitian who can provide personalized advice and ensure the approach is safe and appropriate for you.

Additionally, focusing on long-term sustainable habits that include a balanced diet, regular exercise, and a healthy lifestyle is crucial for maintaining weight loss and overall well-being.

How much weight can you lose on the Fast 800 diet in 12 weeks?


The amount of weight you can lose on the Fast 800 diet in 12 weeks can vary based on individual factors such as starting weight, body composition, metabolism, adherence to the diet, and overall lifestyle. It’s important to note that weight loss is highly individual and can vary significantly from person to person.

The Fast 800 diet, developed by Dr. Michael Mosley, is a low-calorie, low-carbohydrate diet that involves consuming around 800 calories per day for a specific period, typically 8-12 weeks. This level of calorie restriction can lead to significant weight loss, especially in the initial weeks.

On average, individuals following the Fast 800 diet can potentially lose around 0.5 to 1 kilogram (1 to 2 pounds) per week. This would amount to a potential weight loss of 6 to 12 kilograms (13 to 26 pounds) over the course of 12 weeks. However, it’s important to emphasize that individual results may vary.

It’s worth mentioning that sustainable weight loss is not solely about the number on the scale. It’s essential to focus on overall health, body composition, and adopting long-term lifestyle changes that promote healthy eating habits, regular exercise, and a balanced approach to nutrition. Consulting with a healthcare professional or registered dietitian can provide personalized guidance and support for achieving your weight loss goals.

Will my metabolism slow down if I eat 800 calories?

Yes, when you consistently eat only 800 calories a day, your metabolism can slow down as a result of the calorie restriction. This is a natural adaptation mechanism of the body to conserve energy when it senses a decreased calorie intake.

When you consume fewer calories than your body needs for its daily functions and activities, your metabolism may slow down to conserve energy and resources. This can make weight loss more challenging over time because your body becomes more efficient at utilizing the limited calories it receives.

Additionally, severe calorie restriction can also lead to muscle loss. Since muscles contribute to your overall metabolic rate, losing muscle mass can further contribute to a slowed metabolism.

It’s important to note that metabolic changes can vary among individuals, and the degree to which your metabolism slows down can depend on factors such as genetics, age, body composition, and overall health. However, consistently eating a very low calorie intake like 800 calories a day can potentially lead to metabolic adaptations and a slower metabolic rate.

To mitigate the potential negative effects on metabolism, it’s recommended to focus on sustainable weight loss approaches that include a balanced and nutritious diet, regular physical activity, and avoiding excessively low calorie intake for extended periods.

How many pounds can you lose on 800 calories a day?

Losing weight is a complex process that depends on various factors, including your current weight, body composition, activity level, metabolism, and overall health. While a calorie deficit is generally required for weight loss, it’s important to approach it in a healthy and sustainable way.

Eating only 800 calories a day is considered a very low-calorie diet (VLCD) and should be done under medical supervision. VLCDs are typically recommended for individuals with significant excess weight or obesity who require rapid weight loss for medical reasons.

On a VLCD, it’s possible to lose a substantial amount of weight in a relatively short period. However, it’s crucial to note that this rapid weight loss is often due to a combination of fat loss, muscle loss, and water weight reduction.

The general rule of thumb for weight loss is that a deficit of 3,500 calories leads to about 1 pound (0.45 kg) of weight loss. Based on this estimate, if you consistently maintained an 800-calorie-per-day diet and sustained a daily deficit of 1,500 calories, you could theoretically lose around 3-4 pounds (1.4-1.8 kg) per week. However, it’s essential to consider that individual results may vary.

It’s worth noting that such a low-calorie intake is not sustainable in the long term and can have negative health consequences. It can lead to nutritional deficiencies, muscle loss, a slowed metabolism, and other adverse effects. It’s crucial to consult with a healthcare professional or a registered dietitian before embarking on any extreme calorie-restricted diet.

Remember, the most effective and sustainable approach to weight loss is usually a combination of a balanced, calorie-controlled diet and regular physical activity. Gradual, steady weight loss is generally recommended for long-term success and overall health.

Can you lose a stone a month on fast 800?

Losing a stone, which is equivalent to approximately 14 pounds or 6.35 kilograms, in a month can be a challenging goal. The rate of weight loss varies from person to person and depends on various factors such as age, gender, starting weight, body composition, activity level, and overall health.

The Fast 800 is a type of intermittent fasting and low-calorie diet that involves consuming around 800 calories per day for a specific period. It is based on the premise of rapid weight loss through a significant reduction in calorie intake. While some individuals may experience notable weight loss following this approach, it’s important to consider the potential health implications and sustainability of such a restrictive diet.

Losing weight too quickly can have negative effects on your body, including muscle loss, nutritional deficiencies, and a slower metabolism. It’s generally recommended to aim for a gradual and sustainable weight loss of 1-2 pounds (0.5-1 kilogram) per week. This slower rate allows your body to adjust and adapt to the changes more effectively.

Before embarking on any weight loss program, it is advisable to consult with a healthcare professional or a registered dietitian who can assess your specific circumstances, provide personalized advice, and help you set realistic and healthy weight loss goals. They can guide you on creating a well-balanced diet and incorporating regular physical activity to support your weight loss journey in a safe and sustainable manner.

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What happens if you eat 500 800 calories a day?

Eating only 500 to 800 calories per day is an extremely low-calorie diet and can have significant effects on your body. Here are some potential consequences:

  1. Rapid weight loss: Consuming such a low amount of calories will likely lead to rapid weight loss initially. This is because your body will start burning stored fat for energy since it’s not receiving enough calories from food.
  2. Nutritional deficiencies: Severely restricting your calorie intake can make it difficult to meet your body’s nutritional needs. A low-calorie diet typically lacks essential nutrients like vitamins, minerals, proteins, and healthy fats. Over time, this can result in deficiencies, weaken your immune system, and lead to various health problems.
  3. Muscle loss: When you don’t consume enough calories, your body may break down muscle tissue to obtain the energy it needs. This can cause a loss of muscle mass and a decrease in overall strength and endurance.
  4. Slowed metabolism: Consistently eating very few calories can slow down your metabolic rate. This happens because your body tries to conserve energy when it’s not receiving enough fuel. A slower metabolism makes it harder to lose weight in the long term and can lead to weight gain once you increase your calorie intake.
  5. Fatigue and weakness: Insufficient calorie intake can leave you feeling fatigued, weak, and lacking energy. Your body relies on calories for fuel, and when it doesn’t receive enough, it can affect your physical and mental well-being.
  6. Hormonal imbalances: Drastically reducing calorie intake can disrupt hormone production and balance. This can lead to menstrual irregularities in women, decreased fertility, and other hormonal issues.
  7. Nutritional rebound and binge eating: Severely restricting your calories can trigger intense hunger and cravings. Eventually, many people find it difficult to sustain such a low-calorie intake, leading to episodes of overeating or binge eating. This can hinder weight loss efforts and have negative psychological effects.

It’s important to note that consistently following an extremely low-calorie diet without medical supervision is generally not recommended. If you’re looking to lose weight or make dietary changes, it’s advisable to consult a healthcare professional or a registered dietitian who can guide you towards a safe and balanced approach.

How many kg will I lose if I eat 800 calories a day?


The amount of weight you can expect to lose by consuming 800 calories per day depends on various factors, including your current weight, body composition, metabolism, activity level, and overall health. Weight loss is a complex process and individual results may vary.

Generally, a safe and sustainable rate of weight loss is considered to be 0.5 kg to 1 kg (1 lb to 2 lbs) per week. This rate allows for gradual and healthier weight loss while minimizing the risk of muscle loss and nutritional deficiencies.

To estimate the potential weight loss, you can use a rough guideline that suggests a calorie deficit of about 7700 calories leads to approximately 1 kg (2.2 lbs) of weight loss. This estimation is based on the assumption that 1 kg of body weight is equivalent to roughly 7700 calories.

If you’re consuming 800 calories per day, you would have a significant calorie deficit. However, it’s important to note that sustaining such a low-calorie intake can have negative effects on your health, as mentioned earlier. Additionally, the initial weight loss may include a combination of water weight, muscle loss, and fat loss.

If you’re considering weight loss, it’s recommended to consult with a healthcare professional or a registered dietitian. They can help you develop a personalized and sustainable plan based on your specific needs and goals.

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