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MAR 17, 2024

Understanding Calorie Deficit: A Guide to Fitness and Weight Loss


What exactly is a calorie deficit and how do you achieve it? We cover these answers and more.

Read time: 4 minutes

No doubt on your hunt for the best ways to stay in shape, you’ve come across the phrase “calorie deficit”. And, sure, that sounds scientific but what does calorie deficit actually mean and how can it help you keep the pounds off?

Well, at its core, a calorie deficit occurs when you consume fewer calories than your body needs to maintain its current weight. And that’s kinda it: a balance between burning more calories than you’re eating, which forces your body to use stored fat for energy, ultimately leading to weight loss. In fact, it’s so simple that it seems both obvious and a little insulting. But there’s more to it andbefore you suddenly embark on your own calorie deficit routine, you should know the full extent and details behind it.

Pros of a Calorie Deficit

  • Effective Weight Loss: Creating a calorie deficit is scientifically proven to help lose weight. By consuming fewer calories than your body burns, you're guaranteed to see results over time.
  • Flexibility: You can achieve a calorie deficit in various ways – eating less, exercising more, or a combination of both. This flexibility allows for a personalized approach to weight loss.
  • Improved Health Markers: Losing excess weight through a calorie deficit can lead to improved blood pressure, cholesterol levels, and reduced risk of chronic diseases.

Cons of a Calorie Deficit

  • Potential Nutrient Deficiency: Without careful planning and monitoring, cutting calories can lead to a lack of essential nutrients, affecting your overall health.
  • Muscle Loss: If the deficit is too large or if you're not consuming enough protein, you risk losing muscle mass along with fat.
  • Metabolic Adaptations: Over time, your body can adapt to the reduced calorie intake by slowing down your metabolism, making further weight loss more challenging.

Understanding Basal Metabolic Rate (BMR)

So, yeah, there’s a risk when charging blindly into a calorie deficit routine. That’s why understanding the science is so crucial. And this is where your Basal Metabolic Rate (BMR) comes in.

Your BMR is the number of calories your body needs  to perform basic life-sustaining functions, like breathing, circulation, and cell production, while at rest. It accounts for about 60-75% of your daily calorie expenditure, making it a critical factor in determining your overall calorie needs.

To use your BMR for weight loss, you'll first need to calculate it, which can be done using various online calculators or formulas like the Harris-Benedict equation:

  • BMR for Men = 66.47 + (13.75 weight [kg]) + (5.003 size [cm]) − (6.755 age [years])
  • BMR for Women = 655.1 + (9.563 weight [kg]) + (1.85 size [cm]) − (4.676 age [years])

And once you know your BMR, you can add calories based on your activity level to find your maintenance calories (that’s the amount you need to consume to maintain your current weight). From there, creating a deficit is a matter of subtracting a set number of calories (usually 500 per day) to achieve that desired weight loss.

Achieving Calorie Deficit

So, say you’ve consulted a medical professional, you’ve calculated your BMR, what now? How do you go about achieving a calorie deficit? Really, it comes down to three simple changes:

Monitor Your Diet

Use a food diary or app to keep track of what you eat. Aim for a balanced diet rich in fruits, vegetables, lean proteins, and whole grains.

Increase Physical Activity

Incorporate cardio and strength training into your routine. More activity means a higher calorie burn.

Make Small, Sustainable Changes

Rather than drastic cuts, make small adjustments to your diet and activity levels that you can realistically maintain over time.

Proposed Timeline for Monitoring Progress

Even if you’re convinced this is the route for you, treat it like a science experiment. After all, there’s no point hammering away at something that isn’t giving you the results you want to see. As such, try adopting a reduction of 500 calories per day and monitor your results over a period of three months.

Week 1-2

Focus on establishing your new eating and exercise habits. Don't worry too much about the scale, simply pay attention to how you feel.

Week 3-4

By this point you should start to see some weight loss. If not, reassess your calorie intake and output.

Month 2

Evaluate how your body is responding. This is the real crunch time. If you're consistently losing 1-2 pounds per week, you're on the right track. If you're losing more, you might be cutting too many calories.

Month 3 and Beyond

By now, you should have a good handle of what works for you. If your weight loss has plateaued, consider adjusting your calorie intake or increasing your physical activity.

One Last Point of Note

While the principle of a calorie deficit is straightforward, its application is deeply personal. Factors like age, gender, weight, and lifestyle mean that what works for one person might not work for another. Remember, this guide is just a starting point, and a calorie deficit may not be for you but exploring it can offer significant benefits. As always, consult with a healthcare provider before making significant changes to your diet or exercise routine.

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Written by Matthew Stogdon

Matt has been writing for two decades, across print and digital media. He is also an accomplished filmmaker, with several accolades under his belt.

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