I cycled for four hours but my calorie target did not go up. Is the total daily energy chart wrong, or useless if it does not count exercise?
It was already expected, and included in the day’s target.
Gyroscope calculates your TDEE: total energy expenditure, which includes all factors like exercise. TDEE means BMR plus exercise calories, and based on your typical amounts it was already predicted and factored in. The daily allocation for exercise may be a little lower than what you did in an epic session, but then the next day it may be near 0, so the average is designed to be a realistic total based on a period of a few weeks.
And if you did indeed start exercising 5-10x more than before every day, then your calorie targets will start to go up in the next calculation within a few days.
If your Apple Watch says a workout was a certain high amount of calories, that doesn’t mean your total for the day has increased by that amount. It could very easily pull from other parts of the day, so your total expenditure remains surprisingly close to what was expected.
How is the target calculated?
There are two approaches to calculating this.
One approach that some apps take is to just calculate your BMR, and then add on workouts separately on top. This feels cool, but is very error prone. It misses massive aspects of how the body actually works, and also it is very chaotic to not know how much you can eat until you’ve checked data from your watch.
Study Stanford researchers tested seven wrist-worn devices, including the Apple Watch, against lab measurements in 60 people sitting, walking, running and cycling. Heart rate was mostly accurate, but no device estimated energy burn with less than 20% error. The Apple Watch had the lowest overall error. What it means: Watch calories are a rough guide, which is why the target leans on your weight trend. |
The harder calculation is to look at weeks of activity and find your true average, and make a realistic budget based on that. This requires understanding your exercise, walking, and more. Even things like sleep, stress and weight changes get factored in to make it more accurate—all of which affect your calorie usage.
Study In 332 adults from five countries, total daily energy burn measured with doubly labeled water rose with physical activity at lower activity levels, then plateaued for the most active people. What it means: Moving more is great for fitness and health, and past a moderate level it adds little to the calorie side. |
Then you have a more stable and predictable calorie target for the day. Some days you may use slightly more and some slightly less, but the idea is that over the course of a week they do add up.
Where can I see it?
This is shown in your Targets section, and you can see how it changes over time or for each day in the Total Energy (TDEE) chart in Trends. That chart estimates each day on its own, so a long ride can show up there as a bigger day, while your target stays at your average.
This will also show your net calorie surplus or deficit. It is important to remember these are just estimates—then you will also want to look at your weight graph and see if things are turning out as expected or need adjustment.
Can I eat more on some days?
Imagine you get paid your salary once a month, a big number. Does that mean you can spend $0 the other days of the month because you didn’t get paid then? No, you still have the money from before or the money coming in next month. So what you can do is budget it to spread it across evenly: roughly 1/30 per day (after subtracting big expenses like tax and rent).
Similarly, you can take your typical daily expenditure (which could be a little higher on some days, like workout days, and a little lower on others) and spread that out for your food targets.
Now you could eat less during the week and more during a weekend or party. It doesn’t need to be exactly the same amount on every single day, though for most people this is the safest and simplest strategy.
But what matters the most is the averages over time, so if you want to be a bit over on some days and a bit under on others, you can still keep an eye on your total average.
What about a really big day?
Your target is calculated from your last 25 days of activity, including every workout and your steps, and updates about once a week. Adding a ride on top again would count it twice.
Two things make a single day’s burn smaller than it looks. The body makes up for about a quarter of the calories a workout burns by spending less energy on everything else. And watch calorie numbers are off by 20% or more, even on the best devices.
Study Across 1,754 adults measured with doubly labeled water, the gold standard for daily energy burn, the body offset about 28% of the extra calories burned through activity by spending less on its basic functions. Only about 72% showed up in the day’s total, and the offset was larger in people with more bodyfat. What it means: A workout usually earns less food than the number on your watch suggests. |
On a big day like a four-hour ride, eat more if you are hungry, especially protein and carbohydrates for recovery. You can also ask your coach to change your target any time.
Read the calorie guide for more detailed stats and mechanisms of how calorie numbers are calculated and how the body works under the hood.
Our essay on calories covers energy and how the body uses it.