How the numbers work

The short version

Food data

Common foods: USDA FoodData Central

Vital bundles the USDA FoodData Central SR Legacy dataset, about 6,711 foods, so common foods search without a connection. It is published by the US Department of Agriculture and is in the public domain. The values are reference averages from lab measurements of samples, so a particular piece of chicken will not match exactly.

Packaged foods: Open Food Facts

Barcode scans and packaged-food search use Open Food Facts, a free database that volunteers and food companies add to, under the Open Database License. Anyone can add or change a product, and Open Food Facts gives no assurance that its data is accurate or complete. Looking up a barcode sends only the barcode number.

The calories-against-macros check

Protein and carbohydrate give about 4 calories a gram and fat about 9 (7 for alcohol). When Vital reads a product, it adds those up and compares the total with the calories listed. It allows for the two label conventions (US labels count fiber inside carbohydrate, and EU labels do not), a margin of 15% when fiber is known and 25% when it is not, and extra room for label rounding on small servings. If the listed calories fall outside that range, Vital shows a notice before you log the food.

The check catches a record whose calories do not match its own macros. It cannot catch a record that is consistently wrong, or the wrong product. US labels are allowed a margin of their own, which is why the check is generous.

Targets and the calculators

The app and the free calorie calculator use the same math. The full walk-through is an article; here are the pieces.

Resting burn, men:    10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5
Resting burn, women:  10 x weight (kg) + 6.25 x height (cm) - 5 x age - 161
Maintenance  = resting burn x activity factor
Target       = maintenance + goal adjustment, rounded to the nearest 10 calories

• Mifflin-St Jeor. Fitted in 1990 to measurements of 498 healthy adults aged 19 to 78. Less reliable outside that age range, and for anyone pregnant, breastfeeding or managing a medical condition.
• Activity factors: 1.2 (mostly sitting), 1.375 (light exercise), 1.55 (moderate) and 1.725 (hard training). A convention, not measurements.
• Goal pace: for losing or gaining, 0.25%, 0.5% or 0.75% of body weight a week, turned into calories at 3,500 calories per pound. Some goals use a fixed adjustment instead: maintain and general health add nothing, recomposition takes off 150, and performance adds 100.
• The 3,500 rule is rough. It fits people with a lot of body fat and overstates the deficit per pound lost for leaner people (Hall, 2008). Vital uses it for the starting target, and the Progress screen compares your real pace with the plan.
• Protein: 1.6 (standard), 2.0 (high) or 2.4 (very high) grams per kilogram of body weight, within the ranges in the protein article. Fat is 25% of calories. Carbs are the calories left, at 4 per gram.
• Training days: on scheduled training days Vital adds a bonus to your calories, 200 by default, up to 600, or zero if you turn it off. It is a round number, not a personal measurement.

Trends and charts

• Weight trend. One weigh-in is noise: water, salt, and what is in your gut all move the scale. Vital draws a smoothed line by fitting a short straight line through the readings around each weigh-in, with nearby days counting most and anything beyond two weeks away counting for nothing. Readings that sit far from their neighbors are set aside. A missing stretch of days means fewer data points, never a made-up value.
• Weekly pace. Your trend over recent weeks, shown as pounds a week and as a share of body weight, with a likely range. Weight responds slowly to a change in eating, so a pace is a description of the past, not a prediction.
• Estimated maintenance (a Premium feature) works backward: what you ate, minus the energy in the weight you gained or lost. It is shown as a range with a confidence label, or not at all when there is too little data, and it is only as good as your food log.

Workouts

• Estimated one-rep max uses sets of 1 to 10 reps, with the formula you pick in Workout settings: Brzycki (the default), Epley, Mayhew or Wathan. The free estimator shows Epley and Brzycki: Epley: weight x (1 + reps / 30) and Brzycki: weight x 36 / (37 - reps). One rep is its own max. All of them are population formulas, and past about 10 reps they stop being reliable.
• The muscle map counts one set for each main muscle of an exercise and half a set for each helper muscle. Its color bands (under 5, 5 to 9 and 10 or more sets) are a visual guide taken from resistance-training research. They are never a rule, and mobility drills count for nothing.
• Personal records are compared on your logged sets. Edit or delete a set and your records update.

What is exact and what is an estimate

Exact: the sum of the foods you logged, the weight lifted in a set, the number of days you logged, and a streak count. Estimates: everything that says "about", every target, every trend, every one-rep max, and every food number, because food data is an average of something. When the weekly check-in fills in a day you did not log, those entries are marked as estimates and never count toward streaks or badges.

What Vital never claims

• That a food number is right. Vital shows the source and flags what looks wrong; it cannot promise an entry.
• Medical advice, diagnosis or treatment. Vital is a tracking tool, not a medical device. Talk to a doctor or dietitian before big changes, especially with a medical condition, a history of disordered eating, or if you are pregnant.
• That a target is right for your body. Targets are a starting point you can edit.
• That a recipe is safe for an allergy. Recipe filters are a convenience.
• That screen time is read automatically. You enter the total.
• That it syncs with Health Connect, Apple Health or a watch. It does not, in this version.
• That it has a built-in AI. It has none in the first release, and AI replies from a key or an assistant you connect can be wrong.
• That its database is verified, its numbers are the most accurate, or anything is clinically validated.

Found a number that looks wrong? Email support@vitalmacro.com with the product name or barcode and what the label says.

Sources

1. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-247. doi:10.1093/ajcn/51.2.241
2. Hall KD. What is the required energy deficit per unit weight loss? Int J Obes 2008;32(3):573-576. doi:10.1038/sj.ijo.0803720
3. Jager R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20. doi:10.1186/s12970-017-0177-8
4. Morton RW, et al. Protein supplementation and resistance training-induced gains in muscle mass and strength: a systematic review and meta-analysis. Br J Sports Med 2018;52(6):376-384. doi:10.1136/bjsports-2017-097608
5. Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. J Phys Educ Recreat Dance 1993;64(1):88-90. Epley B. Poundage chart. Boyd Epley Workout, 1985.
6. U.S. Department of Agriculture. FoodData Central (public domain). Open Food Facts (ODbL) and its terms of use. 21 CFR 101.9 (US nutrition labeling).

Written November 5, 2026, from the app as it is now. If the app changes, this page changes with it.