Muscle gain

Eating enough is harder to verify than eating less

In a deficit you can check the scale. In a gaining phase the number goes up either way, and under-fuelling looks like progress until it isn’t. Rysflo reads whether the food covered the training demand, and whether it was absorbed.

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A coach and lifter going over training and nutrition numbers together

Set the goal to muscle gain

The same three signals, scored against building rather than losing.

The signals read differently

Same exhale, opposite interpretation. What counts as a good reading depends on the goal you set.

Acetone that should be low

In a deficit, rising acetone is the goal. In a gaining phase it is a warning: the body has gone to its reserves because the intake did not cover the training demand.

Absorbed, not just eaten

A surplus only counts if the food is absorbed. Hydrogen shows which meals were taken up in the small intestine and which fermented in the colon.

Protein that follows the load

A fixed gram-per-kilo rule does not know what you did yesterday. The target moves with the reading, rising on the days the signals say the demand was higher.

Whether recovery is keeping up

Ethanol is a research read on hepatic and microbial load.1 Read alongside the other two it gives a sense of whether a hard block is being absorbed or accumulating.

Rysflo is a wellness device. It does not build muscle and does not replace coaching — it measures whether the plan you are following is producing the metabolic state it is supposed to.

Taking a Rysflo reading between sets in the gym

What under-fuelling looks like

A reading in a gaining phase might come back with acetone elevated and hydrogen calm. Read against a muscle-gain goal, that is not a good day: digestion is fine, but the body has gone to stored fat because intake fell short of what the training asked for.

The instruction that follows is specific — raise intake around the session rather than across the day — and it arrives the morning after, not at the end of a stalled block.

How it fits a surplus

Four steps, sixty seconds a day.

  1. Set the goal to muscle gainThe same three signals, scored for building rather than losing.
  2. Read each morningFasted, before coffee, before the day’s food confuses the picture.
  3. Eat to the numbersProtein, carbohydrate, fat and fibre in grams, weighted toward the training window when the reading calls for it.
  4. Confirm it landedLow acetone and calm hydrogen the next morning is the evidence that the surplus was real and absorbed.

Sources

  1. Breath acetone correlates with capillary beta-hydroxybutyrate in type 1 diabetes — PMC12014577.

Acetone and hydrogen have decades of clinical use behind them. Endogenous ethanol is a research marker rather than a diagnostic one, and the combined three-analyte protocol has not been tested as an intervention. What is established, and what is not.

Measure it tomorrow morning

$29 a month for twelve months, device included.

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