Paul Booth is a performance nutritionist and exercise physiologist who works with elite ultra-endurance athletes and teams, including the Salomon International team, and was the nutritionist behind both the men's and women's UTMB winners in 2025, Tom Evans and Ruth Croft. We cover the science and practice of fuelling: how many carbs you actually need, why the high-carb trend has run ahead of the evidence, and how to get hydration and electrolytes right for triathlon and ultra-endurance racing.