How many calories should I eat to lose weight? The truth about calorie deficits

Losing weight often boils down to a simple equation: calories in, calories out (CICO). This simply means you have to consume fewer calories than you burn. Still, figuring out the magic number for weight loss isn’t always straightforward, and as a nutritionist, many clients have come to me confused about this process.

I have found that answering the question, “How many calories should I eat to lose weight,” depends on various factors, including your age, gender, height, weight, and activity level. It also requires a balance between creating a calorie deficit and providing your body with enough energy to function optimally.

Below, we have explored the key variables that influence your calorie needs, how to calculate them, and tips to make your weight loss journey effective and sustainable.

Factors that determine your calorie deficit

Age

As you age, your metabolism slows, reducing the number of calories your body burns at rest. Younger individuals tend to have higher calorie needs because their bodies are still growing, repairing, and maintaining higher levels of activity.

Gender

Men typically require more calories than women due to higher muscle mass and faster metabolism. Hormonal differences also play a role in fat storage and energy expenditure.

Height

Taller individuals generally need more calories than shorter people. This is because they have a larger body surface area, which requires more energy to maintain basic functions. Taller individuals also likely weigh more than shorter people.

Weight

Your current weight significantly impacts how many calories you burn. Heavier individuals have higher basal metabolic rates (BMR) and thus need more calories to sustain their body weight.

Activity level

Your activity level, including both daily movement and structured exercise, directly affects how many calories you burn. Sedentary individuals need fewer calories, while highly active people require more to fuel their energy demands.

How to use a calorie calculator

Here’s a simple step-by-step guide to using a calorie calculator:

1. Input your personal information: Enter details like age, gender, weight, height, and activity level. Any good calculator will provide a form so that you can fill in these details. They are what help the calorie calculator determine your daily calorie needs.
2. Choose your goal: Specify if you want to maintain weight, lose weight, or gain weight. The calculator will adjust calorie recommendations accordingly.
3. Review your results: The calculator will provide an estimate of the calories you need per day to reach your goal. It might also suggest a breakdown of macronutrients (carbs, proteins, and fats).
4. Track your intake: Use the result as a guideline to plan meals and monitor your calorie consumption using food labels or apps.

What is a healthy calorie deficit?

Reports on how many calories one should drop to lose weight and still maintain good health vary. A 2021 paper published in the Journal of Obesity and Metabolic Syndrome recommends a “deficit of 500 – 750 calories per day” as an initial weight loss strategy.

Another research paper suggests that even when you lower calorie intake by less than 100 calories and increase physical activity, you’d still lose some weight because you’re putting yourself in a deficit.

Looking at these numbers, it is evident that sustainability is really important in weight loss. Most renowned sources and fat loss professionals agree that a healthy calorie deficit typically ranges from 500 to 1,000 calories per day. This range allows for a safe and sustainable weight loss of about one to two pounds per week.

A 1,000-calorie deficit is already on the high side. Going above that may not be sustainable as it could cause muscle loss, hormonal imbalances, and nutritional deficiencies.

How to adjust your calories when you hit a plateau

1. Recalculate your needs: As you lose weight, your calorie requirements will decrease. Use a calorie calculator to update your daily needs based on your new weight.
2. Create a small deficit: You can try reducing your intake by 100–200 calories per day. Go up to a 500-calorie deficit if it feels comfortable, but avoid drastic cuts to prevent muscle loss, energy dips, and constant hunger.
3. Reassess your macros: Adjust the balance of carbs, proteins, and fats. Increasing protein can help preserve muscle and boost metabolism.
4. Incorporate exercise: Add strength training or cardio to burn extra calories without cutting more food. Strength training also helps preserve or build muscle mass, which boosts your metabolism and helps burn more calories at rest.

How often should your calorie intake change?

Your calorie intake should change as you make progress with weight loss. Experts recommend lowering your calories by a small amount every time you lose five to 10 pounds.

However, it may be better to wait until the number on the scale stops going down. Typically, this indicates that your body has gotten used to your former deficit and has redistributed resources to effectively utilize less energy. At this point, reducing calories again is ideal.

Depending on how your body is reacting to a calorie deficit, you will need to lower your calorie intake every few weeks until you’re satisfied with how much weight you’ve lost. Another approach, apart from lowering calories, is increasing activity. This will increase the number of calories you burn, increase your calorie deficit, and cause more weight loss.

Tips for a successful weight loss journey

• Set realistic goals: Aim for a steady weight loss of one to two pounds per week for sustainable results.
• Track your intake: Use apps or journals to log food and stay within your calorie target.
• Prioritize protein: Add lean protein to every meal to keep you full and preserve muscle.
• Eat nutrient-dense, low-calorie foods: Focus on fruits, vegetables, whole grains, and healthy fats. Avoid heavily processed foods that have many calories and a small amount of healthy nutrients.
• Stay hydrated: Drinking plenty of water helps control hunger and supports metabolism.
• Be active: Combine strength training with cardio for optimal fat loss and muscle maintenance.
• Plan meals: Prep healthy meal options in advance to avoid impulsive, unhealthy choices.
• Be patient: Progress takes time. Celebrate small wins and stay consistent.
• Get enough sleep: Poor sleep can disrupt hunger hormones and hinder weight loss. Not sleeping properly also increases stress, which can affect your adherence to a calorie deficit.
• Seek support: Join a community, work with a coach, or rely on friends for encouragement.

Frequently asked questions

Does eating 1,200 calories a day help you lose weight?

Eating 1,200 calories per day can lead to weight loss for some individuals, especially those with lower energy needs. However, it’s crucial to ensure this calorie level provides sufficient nutrients. Consult a healthcare provider before adopting such a low-calorie plan.

Can I lose weight on 1,500 calories a day?

Consuming 1,500 calories a day can support weight loss for many people, particularly those with moderate activity levels. The effectiveness depends on your specific calorie needs and how well this deficit aligns with your goals. It may be better to start slowly, cutting out only 500 calories at first, to allow your body to get used to the deficit.

How do you lose three pounds in a week?

To lose three pounds in a week, you need a calorie deficit of approximately 10,500 calories (3,500 calories per pound). You’d have to eat/train in a 1,500-calorie deficit every day to achieve this goal. Such rapid weight loss may not be sustainable or healthy for everyone, so proceed with caution and seek professional advice.