# Protein, fat and carbohydrate The day's macronutrients, which VT reads more than the calorie total: protein against your lean mass, carbohydrate against your glucose. Type: biomarker · Unit: g/day · Domain: Nutrition & Energy Balance · Accuracy: Self-reported · Importance: Core Also called: macros, macronutrients, protein intake, carbs, carbohydrate intake, fat intake, fiber ## In one sentence The grams of protein, fat and carbohydrate in what you logged, which VT reads more closely than the calorie total, because each one speaks to a different part of your record. ## Why it matters The three macronutrients carry the day's energy (about 4 kilocalories per gram of protein or carbohydrate, 9 per gram of fat), and each has its own conversation with the rest of your data. Protein against your lean mass: in a meta-analysis of 49 trials with 1,863 adults, protein supplementation increased the lean mass and strength people gained from resistance training, with no further gain in lean mass above a total intake of about 1.6 grams per kilogram of body weight a day, and a smaller effect with increasing age (Morton 2018). Carbohydrate against your glucose: the amount and kind in a meal is the first thing that sets its peak and its two-hour area, and the meal library is where that shows. Fat against your lipids: the fatty-acid balance of what you eat moves the lipid panel over months (see the bloodwork entries). Fiber, which VT logs as its own nutrient, against almost everything: in the Lancet's series of systematic reviews, the highest fiber consumers had 15 to 30 percent lower all-cause mortality and lower incidence of several conditions than the lowest, with the largest associations at 25 to 29 grams a day (Reynolds 2019). ## What moves it What you choose; the log's completeness; and the food database behind the app you log with, which is where most macro errors come from. Restaurant and takeaway meals are the least reliable entries. ## How to log well Log the protein source and the carbohydrate source of every meal even when you skip the rest; those two carry most of the information. A kitchen scale for a week teaches portion sizes for a year. ## How Vitality Tracker uses it Protein is read against your daily protein target, built from your lean mass; carbohydrate against the meal library's glucose responses; the three are charted as your daily split, with counts of the days you reached the protein target. When you log in VT, the calories are worked out from the three unless you enter your own figure. Eir reads the macros when it explains a glucose response or a lean-mass trend. ## How far to trust the number Self-reported, with the database's error on top; protein and carbohydrate from whole foods are usually close, fat from cooking is usually under-counted. ## Method Grams per macronutrient from the meal log; energy = 4 × protein + 4 × carbohydrate + 9 × fat; alcohol is logged in standard drinks and not added to the calorie total. ## Sources 1. Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med 2018;52:376–84. [doi:10.1136/bjsports-2017-097608](https://doi.org/10.1136/bjsports-2017-097608) 2. Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet 2019;393:434–45. [doi:10.1016/S0140-6736(18)31809-9](). ## Related - [Energy intake](https://vitalitytracker.app/knowledge/energy-intake) - [Daily protein, fiber and water targets](https://vitalitytracker.app/knowledge/daily-protein-fiber-and-water-targets) - [Peak rise](https://vitalitytracker.app/knowledge/peak-rise) - [Two-hour incremental area under the curve](https://vitalitytracker.app/knowledge/two-hour-iauc) - [Fat mass and lean body mass](https://vitalitytracker.app/knowledge/fat-mass-and-lean-body-mass) - [Why log meals even if you are not trying to lose weight](https://vitalitytracker.app/knowledge/why-log-meals) Reviewed October 2026 · v1 Source: https://vitalitytracker.app/knowledge/protein-fat-and-carbohydrate