Mr Z
Do AI Fitness Coaches Actually Work?
Francesco Zen, founder of ZTraining · Last updated June 19, 2026
A real example
A real example A friend of mine, not a client I'd ever personally coached, started using Mr Z to re-evaluate her existing fat loss plan. That plan had been built entirely around calorie counting, with no real dietary or health guidance behind it. She'd been dealing with low energy, had fainted on one occasion, and was experiencing hair loss. Mr Z suggested specific foods to support hair strength, made better sense of her calorie intake by adding real nutritional guidance, and picked up on a sleep disruption she hadn't even realised was happening, simply by asking the right questions over time. She still uses it today, without stress, just pulling out her phone whenever something comes up.
Why this matters more than the numbers
Calorie counting on its own can't catch a hidden sleep problem or recommend the right food for a symptom that looks unrelated on the surface. That kind of judgment is what separates an AI coach that genuinely works from one that's just doing arithmetic with a friendlier interface.
Related: Why generic fitness apps don't work for most people · An AI coach that actually knows coaching
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.