Measurements & labs

Three sections in one tab

The Measurements tab is divided into three sections: Body measurements, Clothing sizes, and Lab results. Each one tracks a different kind of progress that the scale alone can't capture.

Non-scale victories are real wins. A shrinking waist or a new clothing size can be just as motivating — sometimes more so — than a lower number on the scale.

Body measurements

DayByDay tracks three key body measurements: waist, chest, and neck. Each one gives you a different window into how your body composition is changing.

• ✦Waist — measured at the narrowest point, typically around your navel. Waist circumference is one of the most clinically relevant measurements for cardiovascular and metabolic health.
• ✦Chest — measured at the widest point across your chest. Useful for tracking changes in upper body composition.
• ✦Neck — measured around the mid-neck. Neck circumference is used in formulas for estimating body fat percentage and is also a marker in sleep apnea risk assessment.

The waist trend chart

Just like the weight trend chart, the waist chart plots your measurements over time with a smoothed trend line. You can see your progress over 3 months, 6 months, a year, or all time.

Waist circumference often responds to lifestyle changes faster than body weight, because visceral fat (the fat around your organs) is typically what the body burns first. Many people see their waist shrink noticeably before the scale reflects it.

Body composition gauges

Below the measurement charts, DayByDay shows a panel of body composition metrics calculated from your data. These give you a richer picture of your health than any single number.

• ✦BMI (Body Mass Index) — your weight relative to your height. A widely used but imperfect metric — it doesn't account for muscle mass or body composition.
• ✦WHtR (Waist-to-Height Ratio) — your waist divided by your height. Research suggests keeping this below 0.5 is a good general health target.
• ✦RFM (Relative Fat Mass) — a newer formula that uses waist and height to estimate body fat percentage without a scale or body fat measurement device.
• ✦FFMI (Fat-Free Mass Index) — your lean mass relative to your height, useful if you're tracking muscle gain alongside fat loss.

Clothing sizes — non-scale victories

The clothing size tracker lets you log your current shirt, pants, and dress sizes over time. When you size down, DayByDay marks it as a milestone — because it is.

These entries aren't just for vanity. Clothing size changes are a tangible, real-world confirmation that your body is changing, even when the scale seems stuck.

Lab results

DayByDay lets you log your lab results from doctor's visits and track them over time. This is especially useful if you're on a GLP-1 medication, since your provider likely monitors several of these markers regularly.

What each lab marker means

• ✦A1c (HbA1c) — your average blood sugar level over the past 2–3 months, expressed as a percentage. Below 5.7% is normal; 5.7–6.4% is prediabetes; 6.5%+ is diabetes.
• ✦Fasting glucose — your blood sugar level after not eating for at least 8 hours. Normal is below 100 mg/dL.
• ✦Total cholesterol — the overall level of cholesterol in your blood. Below 200 mg/dL is desirable for most adults.
• ✦LDL cholesterol — often called "bad" cholesterol; high levels are associated with cardiovascular risk. Most guidelines aim for below 100 mg/dL.
• ✦HDL cholesterol — often called "good" cholesterol; higher is better. Above 60 mg/dL is considered protective.
• ✦Triglycerides — fats in your blood that rise with diet, inactivity, or metabolic issues. Normal is below 150 mg/dL.

Logging a measurement or lab result

1. 1Tap the Measurements tab.
2. 2Scroll to the section you want — Body, Clothing, or Labs.
3. 3Tap the + button for that section.
4. 4Enter the date and values.
5. 5Tap Save.