Many fitness enthusiasts and dieters turn to apps like MyFitnessPal for a reliable way to track their progress, but a critical question remains: is the data reliable? Specifically, when it comes to exercise, does MyFitnessPal overestimate calories burned? Evidence from both user experiences and scientific research suggests that these apps often provide inflated figures, which can significantly hinder weight loss efforts.
Why MyFitnessPal's Calorie Burn Estimates Are Inaccurate
Several factors contribute to the inaccuracy of MyFitnessPal's calorie burn estimates. The app relies on a combination of self-reported data and basic metabolic formulas, which have inherent limitations.
General Formulas vs. Individual Metabolism
When you set up your MyFitnessPal account, you input your age, gender, weight, and height. The app then uses established formulas, like the Mifflin-St. Jeor equation, to estimate your basal metabolic rate (BMR)—the calories your body burns at rest. While a good starting point, this approach doesn't account for crucial individual differences, such as body composition, muscle mass, diet history, or genetics. A more muscular person, for example, burns more calories at rest than someone with a higher body fat percentage, even if they have the same weight, and the app's standard formula won't capture this nuance accurately.
Flawed Activity Level Selection
Another major source of error comes from how users select their baseline activity level. The app offers choices from 'sedentary' to 'very active'. The problem is that most people overestimate their daily activity. For example, a person with a desk job who works out three times a week might classify themselves as 'moderately active,' but their lifestyle is still predominantly sedentary. By choosing a higher activity level, the app gives them an inflated daily calorie target, leading them to believe they can eat more and still lose weight, which can derail progress.
The Body's Compensatory Response
One of the most overlooked factors is the body's natural response to increased activity. When you burn more calories through a structured workout, your body often compensates by reducing your non-exercise activity thermogenesis (NEAT) for the rest of the day. This means you might unconsciously fidget less, sit more, or move slower to conserve energy. A fitness app or tracker cannot accurately measure these subconscious changes, so it presents a calorie burn number that is higher than the true net effect of your exercise.
The Syncing Problem with Wearables and Double-Counting
Many MyFitnessPal users sync their accounts with third-party wearable devices like Fitbits or Garmin watches to automatically log activity. While convenient, this often exacerbates the overestimation issue.
- Wearable Inaccuracy: Independent studies have shown that wearable devices have a significant margin of error for calorie burn estimates. A Stanford study found errors ranging from 27% to 93% depending on the device. Wrist-based heart rate monitors, for example, can be affected by factors like wrist position, skin tone, and motion, further compromising accuracy.
- Double-Counting Calories: A frequent problem occurs when the app syncs with a fitness tracker. For instance, a person might manually log a 40-minute bike ride, while their Fitbit simultaneously sends calorie data to MyFitnessPal. This can result in double-counting and an extra 500+ 'earned' calories that the user may mistakenly feel entitled to eat. MyFitnessPal's own help pages confirm how it adds calories back in from synced devices and explains the logic of total daily energy partners.
How to Overcome Inaccuracy and Improve Tracking
To get the most out of MyFitnessPal and avoid frustration, it's crucial to adjust your approach. The following steps can help you use the app as a tool rather than a definitive source of truth.
Practical Steps to Improve Accuracy
- Ignore the 'Exercise Calories': The most impactful change is to stop eating back the calories MyFitnessPal says you've burned. The best strategy for weight loss is to stick to a consistent calorie target and let exercise contribute to your deficit without adjusting your intake. If you are concerned about under-fueling, you can increase your intake slightly and monitor your weight over a couple of weeks.
- Choose a Conservative Activity Level: Set your initial activity level to 'sedentary,' especially if you have a desk job, regardless of how often you work out. This ensures your baseline calorie target is realistic and conservative, preventing the app from overestimating your daily needs from the start.
- Cross-Reference Data: Do not rely on one source. Use multiple tools or an online calculator to cross-reference your total daily energy expenditure (TDEE). Better yet, use a manual process of tracking your intake and monitoring your weight over a few weeks. If your weight loss stalls, reduce your calories slightly.
- Embrace Weekly Averages: Instead of fixating on daily targets, view your calorie intake over a week. This allows for flexibility on certain days while maintaining a consistent overall trend. Tracking becomes less restrictive and more manageable in the long term.
- Enable Negative Adjustments (Web Only): For users who consistently wear a tracking device, enabling negative calorie adjustments on the MyFitnessPal website can provide a more accurate picture of your total daily burn. This ensures your target is not only increased by activity but also lowered if your device reports a lower daily burn than MyFitnessPal's internal calculation.
Calorie Estimation Comparison Table
| Feature | MyFitnessPal (Default Settings) | Manual Tracking (Conservative Method) |
|---|---|---|
| Baseline Activity Level | User-selected (often overestimated) | Set to 'Sedentary' for most people |
| Exercise Calorie Adjustment | Automatically adds 'earned' calories | Ignored or adjusted minimally based on trends |
| Calorie Burn Data Source | General formulas and synced wearable data | Consistent, manual estimates or cross-referenced data |
| Accuracy | Prone to significant overestimation | Generally more accurate and conservative |
| Focus | Daily, potentially fluctuating calorie goals | Weekly calorie averages and consistent intake |
Conclusion: Using MyFitnessPal as a Guide, Not a Rule
Ultimately, MyFitnessPal's calorie burn estimates should be viewed as a guide, not a precise rule. The inherent flaws in predictive equations, combined with the significant inaccuracies of wearable devices, make relying on the app's exercise calorie additions a risky strategy for weight management. By adopting a more conservative approach—setting a low activity level, ignoring exercise calories, and focusing on consistent, mindful eating—you can transform MyFitnessPal into a much more effective tool for achieving your goals.
For further reading on overcoming the limitations of calorie tracking apps, a detailed guide on strategies can be found on TriageMethod.
Key Takeaways:
- MyFitnessPal (MFP) overestimates calories burned because it uses general formulas that do not account for individual metabolic differences.
- Wearable device inaccuracies further inflate MFP's calorie burn estimates, with studies showing error margins up to 93%.
- Incorrect activity level selection by users leads to an inflated baseline calorie target, undermining weight loss efforts.
- The body compensates for exercise, reducing non-exercise movement, which is not tracked by the app, leading to a smaller net calorie burn.
- Stop eating back exercise calories and instead use a fixed, consistent calorie goal to achieve more reliable and predictable weight loss.
- Enable negative calorie adjustments (on the website) to ensure the app can provide a more balanced view of your total daily calorie burn.
- Focus on weekly trends rather than daily fluctuations to maintain consistency and a healthier mindset toward your diet and exercise.
