Calorie Numbers Are Approximate, and That Is OK

Every calorie number on your screen is a little fuzzy. Labels, maths, and AI estimates all have small errors. A steady gap still works over weeks, so trust the trend, not the single day.

14 Jul 2026 · Burnie Academy
calorie-tracking honesty approximation weight-trend

You log your lunch. The app shows 620 kcal. That looks exact, but it is not. The real number could be 540 or 700. And that is fine. In this article you will see why every calorie number is a little fuzzy, and why a fuzzy number still helps you lose weight. The trick is to trust the trend over weeks, not one perfect day.

Where your calorie numbers come from

Your daily deficit is built from four numbers. Each one is a guess, not a lab test. First, the food label on a packet. Second, your BMR (basal metabolic rate, the energy your body uses at rest). Third, the portion you actually scoop onto your plate. Fourth, the Burnie AI estimate when you type a meal in words. Each of these carries a small error. Add four small errors together and your daily number can be off by 100 to 200 kcal. That is normal. It is not a bug in the app. It is how all calorie counting works.

Sources: Burnie app facts (source code)

How fuzzy each number is

Packaged food label

US rules allow a packaged food to carry up to 20 percent more calories than the label says. So a bar labelled 200 kcal may legally give you 240 kcal.

Restaurant and takeaway food

In a study of 269 restaurant foods, 19 percent had at least 100 kcal more per portion than the menu claimed. Some had over 250 kcal more.

BMR maths (Mifflin-St Jeor)

Even the best BMR formula lands within 10 percent of the real value for most people. For a 1500 kcal BMR, that is a 150 kcal swing either way.

Your own portion scoop

People often misjudge how much they serve. In one classic study, people underreported their true intake by about 47 percent, mostly from bigger portions than they realised.

Burnie AI meal estimate

When you type 'two roti, a bowl of dal, and sabzi', the AI gives a best-guess number. It is an estimate by design, not a lab measurement.

Sources: 21 CFR 101.9(g)(5), US FDA nutrition labeling rules · Urban LE et al. Accuracy of Stated Energy Contents of Restaurant Foods. JAMA 2011;306(3):287-293. PMID 21771989 · Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate. J Am Diet Assoc 2005;105(5):775-789. PMID 15883556 · Lichtman SW et al. Discrepancy between self-reported and actual caloric intake and exercise in obese subjects. N Engl J Med 1992;327(27):1893-1898. PMID 1454084 · Burnie app facts (source code)

You must track every calorie to the exact single kcal, or your deficit will not work.

mostly false

Mostly false. A real deficit of 300 kcal still works even if your app says 400. The small error is the same every day, so it cancels out over weeks. What breaks a diet is not a 100 kcal label error. It is a 500 kcal portion you forget to log. Stay consistent, log honestly, and let the weekly weight trend tell you the truth.

Sources: Lichtman SW et al. N Engl J Med 1992;327(27):1893-1898. PMID 1454084 · Frankenfield D et al. J Am Diet Assoc 2005;105(5):775-789. PMID 15883556

Use the trend, not the single day

Sources: Lichtman SW et al. N Engl J Med 1992;327(27):1893-1898. PMID 1454084

The bottom line

Calorie tracking is not broken. It is approximate, and that is OK. Labels have legal wiggle room. BMR maths is a close guess. Portions slip. The Burnie AI estimate is a best guess by design. None of this stops you losing weight. A steady, honestly-logged gap still works over weeks. Pair the app with your weekly weight trend, and let the trend be the judge.

Sources: 21 CFR 101.9(g)(5), US FDA nutrition labeling rules · Frankenfield D et al. J Am Diet Assoc 2005;105(5):775-789. PMID 15883556

Calorie Numbers Are Approximate, and That Is OK

Where your calorie numbers come from

How fuzzy each number is

Use the trend, not the single day

Track your food the honest way