700 Calories a Day Weight Loss Calculator
Estimate your weight loss potential on an extremely low-calorie diet and understand the critical factors involved.
Weight Loss Calculator (700 Calorie Diet)
Enter your current weight in kilograms (kg).
Enter your desired weight in kilograms (kg).
This is the fixed daily calorie intake you plan to consume. We've pre-filled it at 700 kcal for this specific calculator.
Sedentary (Low Activity)
Lightly Active (Exercise 1-3 days/week)
Moderately Active (Exercise 3-5 days/week)
Very Active (Exercise 6-7 days/week)
Extra Active (Very strenuous exercise or physical job)
Estimate your total daily energy expenditure (TDEE) in kilocalories (kcal).
700 Calories a Day Weight Loss Calculator: Understanding Extreme Caloric Restriction
Embarking on a weight loss journey often involves significant dietary changes. While many focus on macronutrients and exercise, caloric intake remains the fundamental driver of weight change. A 700 calories a day weight loss calculator can help illustrate the potential outcomes of an extremely low-calorie diet (ELCD). However, it's crucial to understand that consuming only 700 calories per day is a drastic measure with significant health implications and should only be undertaken under strict medical supervision. This calculator is designed for informational purposes to demonstrate the mathematical principles of weight loss under such a severe deficit, not as a recommendation for practice.
What is a 700 Calorie a Day Diet?
A diet restricting daily intake to approximately 700 calories is considered an extremely low-calorie diet (ELCD). For context, the average adult woman requires around 2000 calories per day, and the average adult man around 2500 calories, to maintain their weight, depending on numerous factors like age, activity level, and metabolism. A 700-calorie diet represents a severe deficit from these maintenance levels. Such diets are typically medically supervised for individuals with specific health conditions, such as severe obesity where rapid weight loss is deemed necessary for health improvement, or prior to bariatric surgery.
Who should use this calculator? Individuals who are curious about the theoretical weight loss implications of a very low-calorie diet, or those who are under medical guidance considering or adhering to such a plan and wish to see the projected timeline. It is NOT for casual dieters or those seeking a sustainable, long-term weight loss solution without professional medical oversight.
Common misconceptions about a 700 calorie a day diet:
- It's a quick fix for everyone: While rapid weight loss can occur, it's often water and muscle loss, not just fat, and is unsustainable and unhealthy for most.
- It automatically leads to faster fat loss: The body can adapt to severe restriction by slowing metabolism, making fat loss less efficient over time.
- It's safe without medical supervision: ELCDs carry significant risks, including nutrient deficiencies, electrolyte imbalances, gallstones, fatigue, and heart problems.
700 Calories a Day Weight Loss Calculator Formula and Mathematical Explanation
The principle behind weight loss, regardless of the diet's calorie level, is creating a calorie deficit. Our 700 calories a day weight loss calculator uses a standard formula to project this loss based on the difference between energy expenditure and intake.
Step-by-step derivation:
- Calculate Daily Calorie Deficit: This is the difference between your body's total daily energy expenditure (TDEE) and your fixed daily caloric intake.
Daily Calorie Deficit = TDEE - Daily Caloric Intake - Estimate Weekly Calorie Deficit: Multiply the daily deficit by 7 to find the deficit over a week.
Weekly Calorie Deficit = Daily Calorie Deficit * 7 - Estimate Weekly Weight Loss: It's widely accepted that a deficit of approximately 7700 kilocalories (kcal) results in the loss of 1 kilogram (kg) of body fat.
Estimated Weekly Weight Loss (kg) = Weekly Calorie Deficit / 7700 - Calculate Total Weight to Lose: The difference between your starting weight and target weight.
Total Weight to Lose (kg) = Starting Weight - Target Weight - Estimate Time to Reach Target: Divide the total weight to lose by the estimated weekly weight loss.
Time to Reach Target (Weeks) = Total Weight to Lose (kg) / Estimated Weekly Weight Loss (kg)
Variable Explanations:
| Variable | Meaning | Unit | Typical Range / Input Method |
|---|---|---|---|
| Starting Weight | Your current body weight. | Kilograms (kg) | Positive number (e.g., 50 – 200+ kg) |
| Target Weight | Your desired body weight. | Kilograms (kg) | Positive number, less than starting weight (e.g., 40 – 180 kg) |
| Daily Caloric Intake (Actual) | The number of calories consumed per day. For this calculator, it's fixed at 700 kcal. | Kilocalories (kcal) | Fixed at 700 kcal |
| Activity Level (Daily Burn / TDEE) | Estimated total calories your body burns in a day through basal metabolism and physical activity. | Kilocalories (kcal) | User selects from predefined ranges (e.g., 1500 – 3500 kcal) |
| Daily Calorie Deficit | The net difference between calories burned and calories consumed in a day. | Kilocalories (kcal) | Calculated (e.g., 800 – 2800 kcal) |
| Estimated Weekly Weight Loss | Projected weight loss per week based on the calorie deficit. | Kilograms (kg) | Calculated (e.g., 0.1 – 3.6 kg/week) |
| Time to Reach Target | Estimated duration in weeks to achieve the target weight. | Weeks | Calculated (e.g., 2 – 50+ weeks) |
Practical Examples (Real-World Use Cases)
Let's look at two hypothetical scenarios using the 700 calories a day weight loss calculator. Remember, these are theoretical projections and actual results can vary significantly. These examples are for illustrative purposes only and do not constitute medical advice.
Example 1: Moderately Active Individual Aiming for Modest Loss
Scenario: Sarah is moderately active (burns approximately 2500 kcal daily) and weighs 70 kg. She is considering a medically supervised 700-calorie diet for a short period and wants to understand potential weight loss. Her target weight is 65 kg.
Inputs:
- Starting Weight: 70 kg
- Target Weight: 65 kg
- Daily Caloric Intake: 700 kcal
- Activity Level (Daily Burn): 2500 kcal
Calculations:
- Daily Calorie Deficit = 2500 kcal – 700 kcal = 1800 kcal
- Weekly Calorie Deficit = 1800 kcal * 7 = 12600 kcal
- Estimated Weekly Weight Loss = 12600 kcal / 7700 kcal/kg ≈ 1.64 kg
- Total Weight to Lose = 70 kg – 65 kg = 5 kg
- Time to Reach Target = 5 kg / 1.64 kg/week ≈ 3.05 weeks
Interpretation: In this theoretical scenario, Sarah could potentially lose about 1.64 kg per week, reaching her 5 kg target in just over 3 weeks. This highlights the rapid nature of weight loss on an ELCD, but also underscores the importance of medical monitoring due to the significant physiological stress.
Example 2: Sedentary Individual with a Larger Weight Loss Goal
Scenario: Mark is sedentary (burns approximately 1800 kcal daily) and weighs 100 kg. He is exploring options for significant weight loss under medical supervision and is curious about the timeline with a 700-calorie intake. His target weight is 80 kg.
Inputs:
- Starting Weight: 100 kg
- Target Weight: 80 kg
- Daily Caloric Intake: 700 kcal
- Activity Level (Daily Burn): 1800 kcal
Calculations:
- Daily Calorie Deficit = 1800 kcal – 700 kcal = 1100 kcal
- Weekly Calorie Deficit = 1100 kcal * 7 = 7700 kcal
- Estimated Weekly Weight Loss = 7700 kcal / 7700 kcal/kg = 1.0 kg
- Total Weight to Lose = 100 kg – 80 kg = 20 kg
- Time to Reach Target = 20 kg / 1.0 kg/week = 20 weeks
Interpretation: Mark faces a longer journey to reach his target, estimated at 20 weeks. The weekly weight loss of 1 kg is still substantial, but the longer duration emphasizes that even with a large deficit, significant weight loss takes time. This example also implicitly shows how the body's metabolic adaptation to severe calorie restriction over a prolonged period might alter these projections in reality.
How to Use This 700 Calories a Day Weight Loss Calculator
Using the 700 calories a day weight loss calculator is straightforward. Follow these steps to get your personalized weight loss projection:
- Enter Starting Weight: Input your current body weight in kilograms (kg) into the "Starting Weight" field.
- Enter Target Weight: Input your desired body weight in kilograms (kg) into the "Target Weight" field. Ensure this is less than your starting weight.
- Confirm Daily Intake: The "Daily Caloric Intake (Actual)" is pre-filled with 700 kcal, reflecting the specific purpose of this calculator. You generally cannot change this without altering the calculator's core function.
- Select Activity Level: Choose the option that best describes your daily physical activity and metabolic rate from the "Activity Level (Daily Burn)" dropdown. This estimates your Total Daily Energy Expenditure (TDEE). If you are unsure, it's often best to start with a lower activity level.
- Click Calculate: Press the "Calculate" button.
How to Read Results:
- Main Result (Estimated Weight Loss): This prominently displayed number shows the projected weight you might lose per week.
- Calorie Deficit: This indicates the net difference between calories your body burns and the 700 calories you consume daily. A larger deficit leads to faster theoretical weight loss.
- Estimated Weekly Loss: Confirms the projected weight loss per week.
- Time to Target: Provides an estimate in weeks to reach your specified target weight based on the calculated weekly loss.
Decision-Making Guidance:
- Consult a Professional: The most crucial step before even considering a 700-calorie diet is consulting a doctor or registered dietitian. They can assess your health, determine if such a diet is appropriate, and guide you safely.
- Understand Limitations: This calculator provides a mathematical projection. Real-world weight loss is affected by many biological factors, including metabolic adaptation, muscle mass, hormonal changes, and adherence.
- Sustainability: A 700-calorie diet is rarely sustainable long-term. Focus on creating a balanced, nutrient-dense eating plan that supports your health goals and lifestyle for lasting results.
- Reset and Re-evaluate: If your inputs change or you want to explore different scenarios (e.g., slightly higher intake, different activity level), use the "Reset" button and re-enter your details.
Key Factors That Affect 700 Calories a Day Weight Loss Results
While the 700 calories a day weight loss calculator offers a projection, numerous factors significantly influence actual weight loss outcomes, especially on such a restrictive diet:
- Basal Metabolic Rate (BMR): This is the number of calories your body burns at rest. Factors like age, sex, muscle mass, and genetics heavily influence BMR. A higher BMR means more calories burned, potentially leading to a larger deficit.
- Thermic Effect of Food (TEF): Calories burned digesting and absorbing food. Protein has a higher TEF than carbohydrates or fats. While a 700-calorie diet makes TEF less significant proportionally, protein intake remains crucial for satiety and muscle preservation.
- Physical Activity Level (PAL): As accounted for in the calculator, the more active you are, the higher your Total Daily Energy Expenditure (TDEE). This is one of the most controllable variables for increasing calorie expenditure.
- Body Composition: Muscle tissue burns more calories than fat tissue. Individuals with higher muscle mass will have a higher TDEE. Severe calorie restriction can lead to muscle loss if not managed properly with adequate protein intake and resistance training, which can negatively impact metabolism.
- Metabolic Adaptation: When the body is in a prolonged severe calorie deficit, it can adapt by slowing down metabolism to conserve energy. This phenomenon, known as adaptive thermogenesis, can reduce the rate of weight loss beyond what the calculator projects.
- Hormonal Changes: Extreme calorie restriction can disrupt hormones like leptin (satiety hormone) and ghrelin (hunger hormone), potentially increasing hunger and making adherence difficult. It can also affect thyroid hormones, further slowing metabolism.
- Nutrient Deficiencies: A 700-calorie diet makes it incredibly difficult to meet all micronutrient needs. Deficiencies can impact overall health, energy levels, and even metabolic function.
- Water Retention and Glycogen Stores: Initial rapid weight loss often includes water weight and depleted glycogen stores, which can fluctuate and mask true fat loss.
Frequently Asked Questions (FAQ)
Is 700 calories a day safe?
A 700 calorie a day diet is considered extremely low-calorie and is generally NOT safe for most individuals without strict medical supervision. It carries significant health risks, including nutrient deficiencies, electrolyte imbalances, fatigue, gallstones, and potential heart issues.
Can I lose weight on 700 calories a day?
Yes, mathematically, a severe calorie deficit of 700 kcal/day (compared to a maintenance intake) will lead to weight loss. However, the rate and sustainability are highly variable and often unhealthy without medical guidance.
What is the typical weekly weight loss on a 700 calorie diet?
The calculator estimates around 1-1.6 kg (2.2-3.5 lbs) per week, depending on your activity level and starting weight. However, initial loss might be higher due to water weight, and it can slow down significantly over time due to metabolic adaptation.
How much weight can I realistically lose in a month on 700 calories?
Theoretically, if you maintain a consistent deficit, you could lose approximately 4-6 kg (8-13 lbs) in a month. However, this is a simplified projection. Real-world results are influenced by many biological factors and can be less predictable and potentially unhealthy.
Will my metabolism slow down on 700 calories?
Yes, a prolonged severe calorie deficit like 700 kcal/day will likely cause your metabolism to slow down as your body tries to conserve energy. This is a key reason why such diets are difficult to maintain and often lead to weight regain.
What are the risks of a 700 calorie diet?
Major risks include malnutrition, fatigue, irritability, hair loss, muscle loss, gallstones, electrolyte imbalances, dizziness, constipation, and potential cardiac problems.
Is it better to eat 700 calories spread out or all at once?
For most people, spreading intake across 2-3 small meals can help manage hunger and provide a more consistent energy supply. However, the total daily intake is the primary driver of weight loss. The focus should be on nutrient density within the limited calories.
Can I exercise while eating only 700 calories?
With such a low intake, intense exercise is generally not recommended due to the high risk of fatigue, injury, and potential for dangerous energy depletion. Light activity might be possible but should be carefully monitored. Consult your doctor.
Should I use a 700 calorie calculator for sustainable weight loss?
No. This calculator demonstrates the math of extreme restriction. For sustainable weight loss, focus on creating a moderate deficit (e.g., 500 kcal/day for ~0.5 kg/week loss) with a balanced diet and regular exercise, ideally guided by a healthcare professional.
Weight Loss Projection Chart
This chart visualizes the estimated weight loss over time based on your inputs. It plots your starting weight, projected weekly loss, and target weight.