Methodology
Calorie Deficit Without Losing Muscle
Francesco Zen, founder of ZTraining · Last updated June 19, 2026
Why this approach is different
Body recomposition is the only approach used here, and the deficit it creates comes from the body consuming more glucose through daily activity and training, not from reducing food intake. Cutting calories aggressively isn't a healthy lever to pull, it puts real stress on the brain and cells that depend on stable fuel.
What this protects
Keeping intake stable while increasing output protects muscle far better than a calorie cut does, because the body isn't being starved of what it needs to maintain the tissue it already has. The deficit still happens, just from the other side of the equation.
Related: What is the metabolic setup principle? · How to calculate maintenance calories
Francesco Zen is the founder of ZTraining and ZLIFE, with 18 years of coaching experience working with executives across the UK, US, and UAE. He built Mr Z, an AI coach trained on his methodology to bring the same approach to a wider audience.