Tools

The formula gives a starting figure. Most people hold a target for two to three weeks, watch the scale and the mirror, and then adjust by 100 to 200 kcal. The estimate is less accurate for people who are much heavier or leaner than average. The formula was developed for adults.

Enter calories and body weight, or use the TDEE tool first.

These are the ranges most sports nutrition guidance uses. Protein between 1.6 and 2.4 g per kg covers most people who train. Many people report feeling flat when fat stays below about 20% of calories for long stretches. Carbohydrate takes whatever is left, so it moves the most when calories change.

Any single reading can be a few percent out either way. Measure the same way every two to four weeks and watch the direction of the trend.

Converting the unit does not change the result. Whether a value is high or low depends on the reference range printed next to it on your report.

• Fast 10 to 12 hours if your form says fastingLipids, glucose and insulin read differently after food. Water is fine and helps the draw.
• Book the draw between 7 and 10 amTestosterone and cortisol are highest in the morning and fall through the day; reference ranges assume a morning sample.
• No hard training for 48 hours beforeHeavy sessions push up creatine kinase, liver enzymes (ALT, AST) and sometimes creatinine. On a report that can look like a problem when it is only training.
• Drink water the evening before and the morning ofDehydration concentrates the blood and nudges haematocrit, creatinine and urea upwards.
• No alcohol for 48 to 72 hoursLiver enzymes, triglycerides and uric acid all respond to a big night.
• Pause high-dose biotin (hair, skin and nails supplements) for 48 hours, as labs adviseBiotin interferes with the assays used for thyroid and some hormone tests and can produce false results.
• Sleep normally the night beforeA short night raises cortisol and glucose the next morning.
• Repeat tests under the same conditionsSame time of day, same fasting state, same gap since training. When the setup stays the same, a change between tests reflects a change in you.
• Take your request form and photo IDThe collection centre needs the form on your phone or printed. Any centre in the network on the form will take it, and most do not need an appointment.

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Keep the rest of your routine as it is. The test is most useful when it reflects a normal week, and the doctor knows what you told us you take. Keep taking any prescribed medication as normal. If you are unsure, ask the doctor who prescribed it.

If you are still unsure, the Standard panel suits most people who train. Every panel comes with the portal, and the doctor can discuss any extra markers on the call.