Understanding the Core Concept: Net Calories
At its heart, MyFitnessPal's tracking philosophy is based on Net Calories. This isn't just about the food you consume, but a dynamic equation that factors in your energy expenditure. The basic calculation looks like this:
- $Calories Consumed (Food) - Calories Burned (Exercise) = Net Calories$
Your daily calorie goal in MyFitnessPal is a Net Calories target. This means that if you exercise, the app assumes you have 'earned' extra calories to help you reach or maintain your specific weight goal. For example, if your net goal is 2000 calories, you could eat 2500 calories of food and burn 500 calories exercising to meet that target. It's essentially a calorie budget that you can expand through physical activity.
How MyFitnessPal Calculates Your Baseline
Before any activity is logged, MyFitnessPal uses your personal data to establish a baseline. The app's initial estimate for your daily calorie needs is based on several factors, including your height, weight, age, and a set activity level. This daily estimate assumes a certain level of caloric burn from normal, daily activities.
Many experts and experienced users recommend setting your initial activity level to the lowest option (e.g., Sedentary or Not Very Active). The reason for this is to prevent MyFitnessPal from overestimating your baseline calorie burn. By starting with a lower baseline, you can more accurately 'earn back' calories with the specific, trackable exercises you do throughout the day, providing a more realistic and motivating experience.
The Calorie Adjustment Explained
So, why does MyFitnessPal add calories? This happens when your actual caloric expenditure, based on logged activity, surpasses the app's initial sedentary estimate for the day. This is where the 'Calorie Adjustment' line in your exercise diary comes into play. The adjustment can come from two sources:
Manual Exercise Entry
When you manually log a cardiovascular exercise, the calories burned are automatically factored into your daily calorie budget. If you go for a 30-minute run and log it, MyFitnessPal will add the estimated calories burned to your daily allowance, allowing you to eat more while staying on track with your overall goal. It’s a direct addition based on the exercise you input.
Activity Tracker Syncing
The more complex—and often more confusing—adjustment comes from syncing with a third-party fitness tracker (like a Garmin, Fitbit, or Apple Watch). The process works like this:
- Initial Estimate: MyFitnessPal starts the day with its own estimate of your daily burn, based on your profile and chosen activity level.
- Continuous Sync: Your fitness tracker continuously sends your minute-by-minute activity data to MyFitnessPal throughout the day.
- The Comparison: The app compares the total calorie burn recorded by your device against its own initial estimate for the day.
- The Adjustment: If your device shows you've burned more calories than the MyFitnessPal estimate, the app adds the difference as a positive 'Calorie Adjustment'. Because data is constantly updated, this value can fluctuate throughout the day, becoming more accurate as midnight approaches.
Positive vs. Negative Adjustments
By default, MyFitnessPal only shows you positive calorie adjustments. This means that if your device records fewer calories burned than the app's initial estimate, the adjustment will simply show as zero. However, you have the option to enable Negative Adjustments, which is recommended for the most accurate tracking.
| Feature | Positive Calorie Adjustment | Negative Calorie Adjustment |
|---|---|---|
| Trigger | Your activity tracker's total projected burn is higher than MyFitnessPal's estimated burn. | Your activity tracker's total projected burn is lower than MyFitnessPal's estimated burn. |
| Calorie Impact | Adds calories to your daily budget, allowing you to eat more. | Deducts calories from your daily budget, reducing your total allowance. |
| Setup | Enabled by default. | Must be manually enabled on the MyFitnessPal website under 'Diary Settings'. |
| Why Use It? | Motivates you to be more active by showing the 'extra' calories you've earned. | Provides the most accurate picture of your true calorie budget by accounting for both higher and lower activity days. |
To enable negative adjustments, you must log into the MyFitnessPal website, navigate to 'Settings' and then 'Diary Settings', and check the 'Enable Negative Adjustments' box.
Should You Always Eat Back Exercise Calories?
This is a common question, and the answer is not a simple yes or no. The accuracy of calorie burn estimations from trackers can vary, and relying too heavily on them to dictate your eating can be a risky strategy.
- Consider your goals: If you're aiming for significant weight loss, eating back every calorie you burn might negate your intended deficit. Some find it more effective to see the adjusted total as a 'buffer' rather than a free pass to eat more.
- Listen to your body: If you are intensely training, you might feel genuinely hungry and need the extra fuel. Conversely, if you feel satisfied, there's no need to force yourself to consume the extra calories.
- Focus on overall progress: Instead of fixating on the daily fluctuations, track your weight over time and see if your progress aligns with your calorie budget. Relying solely on estimated numbers can lead to frustration if they don't produce the expected results.
Troubleshooting Calorie Adjustment Issues
- Verify your profile information: Incorrect weight, height, or age can lead to inaccurate calorie burn calculations from the start. Double-check that your stats are up-to-date in both MyFitnessPal and your synced device.
- Check time zone settings: A mismatch between your phone's time zone, your device's time zone, and your MyFitnessPal settings can cause syncing issues and strange adjustment figures.
- Avoid double-counting: Manually logging an exercise that was also tracked by your device can cause MyFitnessPal to double-count the calories. It is best to let one source be the primary record for your activity.
- Monitor the daily changes: The adjustment is a constantly recalculated number. Don't be alarmed if it starts at zero or a low number and increases throughout the day as your activity accumulates.
Conclusion: Making the MyFitnessPal Adjustment Work for You
The calorie adjustment feature in MyFitnessPal is a powerful tool designed to give you a more accurate and responsive calorie budget based on your daily activity. By understanding how the app's baseline estimate interacts with your exercise logs and synced activity trackers, you can take control of your tracking experience. For the most precise data, enabling negative adjustments allows the app to account for days with less activity, but for many, the default positive adjustment can be a motivating way to see how exercise expands their calorie budget. Ultimately, the goal is to use this information to create a sustainable and successful nutrition plan, not to become overly fixated on the daily numbers. Focusing on the bigger picture of your health journey will yield the best long-term results.
