Many people build calorie / macro tracker like OP but they don't build maintenance calorie tracker.
Your app tracks calorie intake, doesn't keep track of total calorie burn of the day (maintenance calorie tracking)
And no, calorie burn from watch is not good enough!
>A 2020 systematic review by Fuller et al. found that consumer wearables often perform poorly at estimating energy expenditure, even when they measure steps and heart rate reasonably well. Across brands like Apple, Garmin, Polar, and Withings, calorie burn estimates frequently showed substantial error, often in the 15–40% range and sometimes exceeding 50%. Wearables can still be useful for tracking trends, but not for precise calorie calculations.
Here's completely free one i built, https://macrocodex.app/ 16,000+ users already.
If the smartwatch data isn’t precise enough to estimate energy expenditure, what data does your website use that is so much better? Also, how much better it is? How do we even know it’s better? (I am not necessarily doubting it’s better, I am just interested in metrics you used)
Method is explained here: https://macrocodex.app/knowledge/rethink/adaptive-tdee/
The actual method used in the app is a bit more complex than this, but I think this explanation is good enough to convey the core idea for now. Later, I plan to publish a more detailed write up.
>Also, how much better it is? How do we even know it’s better?
Very simple! If a car salesman tells you that they use space technology in the engine to improve fuel efficiency, how do you know whether they are telling the truth?
You fill the tank with a specific amount of fuel and drive. If the fuel lasts much longer, you know the technology is actually improving efficiency.
The same idea applies to MacroCodex.
When you eat at maintenance you do not gain weight, when you eat above maintenance you gain weight, when you eat below it, you lose weight.
If you set a goal in the app to gain 1 lb per week and consistently eat the calorie target prescribed by the app, then your actual weight gain should match that rate. If it does, you know the maintenance calories calculated by the app are accurate.
You can choose to set "maintain" or "lose" or "gain".
Thank you! That’s s very thorough explanation on the page you linked and the comment. I’ll certainly look into the app more in the future. Thanks again for taking time to explain and for making the app!