01
Not Medical Advice
ChatRPE's coach is AI and can make mistakes. It helps you log and understand your training, food and body data. It is not a doctor or dietitian, and it does not diagnose or treat any condition.
Check with a doctor before making medical decisions, and before changing your diet or training if you are pregnant, take medication, or have a health condition. If you feel pain, dizziness or shortness of breath while exercising, stop and seek medical attention.
02
How the Coach Cites Sources
When the coach uses information from the web, it links the words that information supports. Tap the link to see the source before you leave the app. When it talks about your own numbers, it links the entry in your log instead.
You can always ask where a figure came from, for example “What's the source for that protein target?” The coach will search and link what it finds. The standard formulas and ranges it relies on are listed below.
03
Body Mass Index (BMI)
BMI is weight in kilograms divided by height in meters squared. For adults, the WHO categories are under 18.5 (underweight), 18.5 to 24.9 (healthy range), 25 to 29.9 (overweight) and 30 or more (obesity). BMI does not tell muscle from fat, so it can misread people who carry a lot of muscle.
04
Calorie Needs (BMR and TDEE)
Resting calorie needs are estimated with the Mifflin-St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, plus 5 for men or minus 161 for women. Daily needs multiply that by an activity factor from 1.2 (mostly seated) to 1.9 (hard training plus a physical job). A systematic review found Mifflin-St Jeor the most accurate of the common equations, but it is still an estimate. Your logged intake and weight trend are the better guide over time.
05
Calorie Deficits and Weight-Loss Pace
Eating fewer calories than you burn leads to weight loss. The common rule that 3,500 calories equals one pound of fat is a rough estimate. It overstates loss over months, because your calorie needs fall as your weight does. For people who lift, losing about 0.5% to 1% of body weight a week is the pace most often recommended for keeping muscle.
Sources
- Hall et al. (2011), Quantification of the effect of energy imbalance on bodyweight
- Thomas et al. (2013), Can a weight loss of one pound a week be achieved with a 3500-kcal deficit?
- Helms et al. (2014), Evidence-based recommendations for natural bodybuilding contest preparation: nutrition
- NIH NIDDK Body Weight Planner
06
Protein Targets
Sports nutrition position stands recommend 1.2 to 2.0 grams of protein per kilogram of body weight a day for active people, and 1.2 to 1.6 g/kg is a common general target. For building muscle, gains level off around 1.6 g/kg, and some people benefit from up to 2.2 g/kg. When lifting in a calorie deficit, lean lifters keep more muscle with higher intakes, roughly 1.8 to 2.7 g/kg.
Sources
- Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM (2016), Nutrition and Athletic Performance
- Jäger et al. (2017), International Society of Sports Nutrition position stand: protein and exercise
- Morton et al. (2018), Protein supplementation and resistance training: a meta-analysis
- Helms et al. (2014), Dietary protein during caloric restriction in resistance-trained lean athletes
07
Strength Estimates and Effort (RPE)
An estimated one-rep max (e1RM) is calculated from a weight and the reps you did with it, using equations such as Epley's. These estimates are most accurate at lower rep counts, roughly 10 or fewer. RPE is rated on the 1 to 10 scale built on reps in reserve, where RPE 8 means you could have done about two more reps.
08
Physical Activity
Adults are advised to get 150 to 300 minutes of moderate activity, or 75 to 150 minutes of vigorous activity, each week, plus muscle-strengthening work on two or more days.