Four numbers to go
Enter age, height, weight and waist to see your check-in.
Headline metric
--waist ÷ height--
--
--
0.300.400.500.600.70
Weight--kg
BMI----
Body fat----
This month, focus on
Since last check-in
Weight----
Waist----
Pace--
gain00.51%1.5%/wk
--
--
Fuel plan
--kcal/day
--
--Protein g
--Carbs g
--Fat g
Body composition
--
--
Lean mass
--
Fat mass
--
Weight at goal fat %
--
FFMI (muscularity)
--
Methods
--
Engine · VO₂ max
--ml/kg/min
--
-40%median for your age+40%
Fitness age----
Source----
Heart-rate zones
--
Blood pressure
--
--
Mean arterial pressure
--
Pulse pressure
--
--
Function
Sit-rise test--
--
Push-ups--
--
Measure the same way every month
When: morning, after the bathroom, before food or drink.
Weight: same scale, same spot on the floor, minimal clothing.
Waist: tape level around your navel, relaxed, at the end of a normal breath out. Don't suck in. Take two readings and use the average.
Neck: just below the Adam's apple, tape sloping slightly down to the front.
Hips: widest point of the buttocks, feet together.
Consistency beats precision: the trend over months is what matters.
Why waist ÷ height is the headline
It's the simplest measure that tracks visceral (belly) fat, the fat that drives diabetes, heart disease and high blood pressure. BMI can't tell muscle from fat; your waist can.
The rule
Keep your waist under half your height. 0.40-0.49 healthy · 0.50-0.59 increased risk · 0.60+ high risk.
The ring
Shows how close you are to the 0.50 line. It fills to 100% when your waist is under half your height.
Burn: resting burn from Mifflin-St Jeor (the most accurate simple formula, including at higher weights), times your activity level.
Pace: set as a % of bodyweight per week, so the target shrinks as you do. 0.5-1% per week is the evidence-backed range for losing fat while keeping muscle.
Guard rails: deficit capped at 1,000 kcal/day, intake never below 1,500 (men) / 1,200 (women) without medical supervision.
Protein: 2.0 g per kg of lean mass while losing (1.6 when holding). Basing it on lean mass instead of total weight avoids absurd numbers at higher body fat.
Milestones
Losing just 5% of bodyweight measurably improves blood pressure, blood sugar and triglycerides; 10% roughly doubles the benefit. Dates assume you hold the pace; real life has plateaus, so treat them as a direction, not a deadline.
Mifflin et al. 1990; NHLBI obesity guidelines; ISSN position stand on protein (Jäger 2017); Look AHEAD / Wing 2011 on 5-10% loss.
Body fat, two ways
RFM (Relative Fat Mass): height and waist only. Validated against DEXA scans in ~12,000 adults; more accurate than BMI.
US Navy method: adds neck (and hips for women). Typically within ±3-4% of lab methods.
If you add your neck, the two are averaged. Bands follow ACE: athletic, fit, average, obese.
Weight at goal fat % answers: if you only lost fat and kept every kg of muscle, what would you weigh at the top of the "fit" band?
FFMI is BMI for muscle only. 18-20 average man (15-17 woman); 22+ clearly trained.
The most oxygen your body can use per minute. Low cardio fitness carries mortality risk comparable to smoking or diabetes, and moving out of the bottom 25% is one of the biggest health wins available.
Where the number comes from
12-min run (Cooper): best if you can run.
1-mile walk (Rockport): great for now. Validated, about ±5 ml/kg/min.
No test: a non-exercise estimate from age, BMI and activity (Jackson). Rough; do the walk test.
Fitness age
The age at which your VO₂ max would be exactly average, using the FRIEND registry of lab-measured treadmill tests.
Cooper 1968; Kline et al. 1987; Jackson et al. 1990; Kaminsky et al., Mayo Clin Proc 2015 (FRIEND); Mandsager et al., JAMA Netw Open 2018.
Heart-rate zones
Max HR uses Tanaka (208 - 0.7 x age), more accurate than 220 - age. With a resting HR, zones use the Karvonen heart-rate-reserve method.
Zone 2 is the highlighted one: you can still talk in full sentences. Two to four sessions of 30-60 minutes a week builds the aerobic base, burns fat, and is easy to recover from. Brisk walking or incline walking counts.
Tanaka et al., JACC 2001; Karvonen et al. 1957.
Blood pressure
Categories: Normal <120 and <80 · Elevated 120-129 and <80 · Stage 1 130-139 or 80-89 · Stage 2 ≥140 or ≥90 · Severe ≥180 or ≥120.
Measure it right
Sit 5 minutes, back supported, feet flat, arm at heart level.
No coffee, nicotine or exercise for 30 minutes before.
Take 2 readings a minute apart, morning and evening, for a week. Use the average.
Weight loss is one of the strongest BP medicines there is: roughly 1 mmHg down per kg lost.
Sit-rise test: in ~2,000 adults aged 51-80, each point gained was linked to about 21% lower mortality. It captures strength, mobility, balance and body weight in one move.
Push-ups: in a 10-year study of men, those who could do 40+ had 96% fewer cardiovascular events than those under 10. Study was men only; use as a direction for women.
Brito et al., Eur J Prev Cardiol 2014; Yang et al., JAMA Netw Open 2019.
Field-test protocols
1-mile walk (Rockport)
Flat ground, 1.609 km. Walk as fast as you can without jogging. Note total minutes and your heart rate the moment you stop (chest strap or watch).
12-minute run (Cooper)
Warm up, then cover as much distance as possible in 12 minutes. A track makes it easy to count.
Sit-rise test
Barefoot. Cross your legs, sit down to the floor, then stand back up. Start at 10 (5 down + 5 up). Subtract 1 for every hand, knee, forearm or side-of-leg support, and 0.5 for any wobble.
Push-ups
Full push-ups, chest to fist height, steady tempo, no rest at the top. Count until form breaks.
Reading your pace
Daily weight swings 1-2 kg from water, salt and food in your gut, which is why monthly check-ins work well.
0.5-1% per week: the sweet spot. Mostly fat, muscle protected.
Over 1% per week: fine for the first month (water), but if it continues, eat a little more and keep protein high.
Under 0.5%: still progress. If your waist is shrinking, you're likely building muscle while losing fat.
The waist is the tie-breaker: if the scale stalls but the tape moves, you're winning.