MacrosFirst learns what you burn from two things you're already tracking: your food log and your weigh-ins. You don't need to log perfectly for that to work, but a few simple habits make a big difference in how accurately MacrosFirst can calculate your expenditure.
This article covers how much data MacrosFirst needs, how to handle partial days, fasting days, and breaks, and why consistent logging matters more than perfect logging.
You don't need to log perfectly for MacrosFirst to work. You need to log consistently.
Here's why. MacrosFirst measures your expenditure by comparing what you log with how your weight responds. Say you always forget to log the tablespoon of oil you cook with, about 120 calories a day. Your logged intake will read 120 calories low, so your measured expenditure reads about 120 calories low too. But your targets are built from that same expenditure, and you'll keep logging the same way, so you still move toward your goal at the rate you chose. Consistent gaps cancel out.
What causes problems is inconsistency: logging every bite some days and only half your meals on others. Those half-logged days look like very low-calorie days, and they pull your expenditure down in a way that doesn't cancel out. The good news is that it's easy to fix, as explained below.
To update your expenditure, MacrosFirst needs food logged on at least 3 of the past 7 days and at least 2 weigh-ins in the past 14 days. Today's food doesn't count until the day is over, since you're probably still logging.
That's the minimum. The more often you log and weigh in, the sharper the picture of what you burn. When you have enough data, your expenditure moves forward each time you weigh in. Between weigh-ins it holds, and when you weigh in next, MacrosFirst goes back and recalculates the days in between using the food you logged on them. When there isn't enough recent data, your expenditure holds where it is rather than guessing, and your expenditure chart labels those days Exp. holding. See Reading Your Expenditure Chart.
MacrosFirst treats three kinds of days differently, and knowing the difference keeps your expenditure accurate.
A day with nothing logged is treated as unknown, not as zero calories, so it's simply left out of the calculation. A partially logged day is different. It counts as a logged day, so if you logged breakfast and lunch but not dinner, MacrosFirst sees a very low-calorie day and can conclude you burn less than you do. Mark those days Incomplete, and they're left out too. And a day you truly didn't eat should be marked Fasting, so MacrosFirst records it as zero calories instead of unknown.
To mark a day as incomplete or fasting:
Open the day in your Journal.
Tap the ... button at the top, then Edit Day Details.
Turn on Incomplete day (left out of calculations for better accuracy) or Fasting (counts as 0 calories without breaking your streak).
A banner on that day in your Journal shows that it's marked. Your weekly check-in also asks you to review the past week and mark any incomplete days, so nothing slips through.
Unmarked partial days add up quickly. Say you really eat about 2,300 calories a day, but on four days a week you only log breakfast and lunch, about 1,200 calories. Your logged average comes out around 1,670 a day, yet your weight holds steady. To MacrosFirst, that looks like someone who burns closer to 1,700 than 2,300, so over the following weeks your expenditure, and your targets, drift lower than they should.
Marking those four days Incomplete fixes it. They're left out, and MacrosFirst learns from the three days you logged fully. If your expenditure ever seems surprisingly low, review your recent days for anything you didn't fully log.
Life happens and MacrosFirst lets you roll with it. If you log loosely while you're away from your normal routine, mark those days Incomplete. If you don't log at all, that's fine too: empty days are left out, and your expenditure holds until you're back.
After a long break, the first few weeks of new data can move your expenditure more than usual but this will settle as your continue to log.
If you'd like a totally fresh start, you can set a new Expenditure Start date, and MacrosFirst will ignore everything before it without deleting any of your data. See Expenditure Settings.
Your weigh-ins matter as much as your food log. Try to weigh in under the same conditions each time, ideally first thing in the morning, after using the bathroom and before eating or drinking. Two weigh-ins every two weeks is the minimum for your expenditure to update, but daily or most days gives you a smoother, more accurate trend weight and lets your expenditure catch real changes sooner.
Don't worry about daily jumps. Water, salt, and carbs move the scale every day, and that’s why MacrosFirst uses your trend weight, not any single weigh-in to separate the signal from the noise. See Scale Weight vs. Trend Weight.
Good data is what makes your targets personal. These articles show where it goes:
"How does MacrosFirst turn my logs into an expenditure?" Energy Expenditure
"Why is my expenditure holding?" Reading Your Expenditure Chart
"How do I start my expenditure fresh after a break?" Expenditure Settings
"What happens at my weekly check-in?" Weekly Check-In
What if my calorie target still looks off? Most surprises come down to a few common causes, and each one has a simple fix: Troubleshooting: My Calorie Target Looks Wrong.
