Most popular diets were not designed to produce fat loss. They were designed for something else entirely.

Developed from epidemiological research on populations with low cardiovascular disease rates in Southern Europe. Designed to reduce heart disease risk and improve longevity. Fat loss is a secondary benefit when caloric intake happens to be below maintenance. Primary design goal: long-term health.

Developed by the National Heart, Lung, and Blood Institute specifically to lower blood pressure. Dietary Approaches to Stop Hypertension. Fat loss is incidental. Primary design goal: blood pressure reduction.

Based on evolutionary theory — eat what our paleolithic ancestors ate. Fat loss occurs when total intake falls below maintenance. Primary design goal: ancestral alignment and elimination of processed food.

A 30-day elimination protocol for identifying food sensitivities and resetting relationship with food. The creators explicitly state it is not a weight loss program. Primary design goal: food sensitivity identification and habit reset.

Developed from research on metabolic flexibility, autophagy, and fasting physiology. Fat loss occurs when the eating window results in lower total intake. Primary design goal: metabolic and cellular health.

Developed at Harvard Medical School in the 1970s specifically to produce rapid fat loss while preserving lean mass. Every element — protein targets, caloric floor, refeed scheduling, resistance training requirement, supplement protocol, defined duration — was designed with fat loss as the primary output. It has been refined by 50+ years of clinical research for exactly this purpose.

A diet designed for fat loss optimises for five variables:

1. Caloric deficit — large enough to produce meaningful fat loss; not so large that lean mass is compromised 2. Protein precision — high enough to preserve lean mass (2.2–3.0 g/kg LBM) throughout the deficit 3. Hormonal management — refeeds to manage leptin; mandatory recovery to manage adaptation 4. Adherence architecture — a defined endpoint that makes short-term intense commitment psychologically sustainable 5. Lean mass protection — resistance training required as part of the protocol, not optional

Most popular diets address zero to two of these. The FLS addresses all five.

If you've tried Mediterranean, Paleo, Whole30, IF, or similar approaches and didn't achieve your fat loss goal — this may not be a failure of willpower or commitment. It may be a category error: using a health-optimisation tool to solve a fat loss problem.

The tools are different. The Fat Loss Sprint is the tool built for the specific job of fat loss.

Yes. The sprint is a time-limited protocol — 14–28 days. After the sprint and mandatory recovery phase, users transition to whatever long-term eating pattern suits them: Mediterranean, whole food, flexible eating, intuitive eating. The sprint is not a permanent replacement for a health diet. It's the tool you deploy when fat loss is the goal — then you return to the pattern that works long-term for health.