Endurance sports, triathlons being the most popular, are the preserve of alpha-males with high disposable incomes and a predilection for gadgets: a potentially great opportunity for product developers. The interest and market in ketone diets in endurance sport training has been rapidly evolving with new supplements and nutritional aides appearing: but the market is fickle. We undertook a market mapping study to assess the extent of opportunities for the launch of a new piece of kit for the endurance sport enthusiast a non-invasive diagnostic measurement of breath acetone as a marker for ketones in the blood.