Lipoly
Your Fat Loss Sprint Guide
Most 'high protein' diets still fall short of the lean mass preservation threshold. The Fat Loss Sprint calculates your exact target from your lean body mass — not a generic RDA.
Most people underestimate their protein requirements during a caloric deficit. Here's what the research shows:
| Recommendation | Protein Target | Context |
|---|---|---|
| General RDA | 0.8 g/kg body weight | Minimum to prevent deficiency — not optimised for fat loss |
| Standard "high protein" diet | 1.2–1.6 g/kg body weight | Better, but below the threshold for aggressive deficit |
| PSMF clinical minimum | 1.2–1.5 g/kg ideal body weight | Established in the 1970s Harvard PSMF research |
| Longland et al. high-protein group | 2.4 g/kg body weight | Produced lean mass gain during 40% caloric deficit |
| **Fat Loss Sprint target** | **2.2–3.0 g/kg lean body mass** | Calculated from actual LBM — most precise, highest protection |
The difference between 0.8 g/kg (RDA) and 2.5 g/kg LBM is significant. For a 75 kg person with 60 kg of lean body mass:
This is not a marginal distinction. It is the variable that determines whether you lose fat or fat-and-muscle during a caloric deficit.
Most protein recommendations use total body weight. The Fat Loss Sprint uses lean body mass — the weight of everything except fat.
Why does this matter? Because the purpose of high protein during restriction is to preserve lean mass. The calculation should be based on the lean mass at risk, not total body weight (which includes the fat you're trying to lose).
For a person with 30% body fat at 80 kg:
Both are high. But the LBM calculation is more precise — it doesn't inflate requirements based on the fat mass you're eliminating.
Protein alone does not preserve lean mass. It requires the mechanical stimulus of resistance training to signal the body to maintain muscle during restriction.
Willoughby et al. (2023): The combination of adequate protein (above 1.2 g/kg) and resistance training is required to substantially mitigate lean mass loss during VLCDs. Either alone is less effective than both together.
The Fat Loss Sprint mandates both: protein at 2.2–3.0 g/kg LBM and 2x/week structured resistance training. Neither is optional. Both are tracked in the app.
Longland et al. (AJCN, 2016): Participants in a 40% caloric deficit consuming 2.4 g/kg/day protein plus resistance training gained 1.2 kg of lean mass while losing 4.8 kg of fat. This is the FLS model validated.
Mettler et al. (2010): Athletes on identical caloric deficits — high protein (2.3 g/kg) vs. standard (1.0 g/kg). High-protein group retained significantly more lean mass.
2.2–3.0 g/kg LBM. Resistance training required. Lean mass protection built in.
See your numbers
Sprint level, calculated macros, and a recommended duration — based on your body composition.
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