Foraging is an increasingly popular past time in Western countries while globally, over 50% of the population depends on wild foods for nutrition or income. Despite interest in the ‘Paleo diet’, few studies have investigated the health effects of full dependence on the exclusive consumption of wild foods—as opposed to modern breed equivalents. Measuring the health impacts of a Mesolithic diet may increase the understanding of how Western humans would thrive, if dependent on the ‘famine foods’ of the past, and whether wild foods improve human health and wellbeing. This chapter examines and defines a Mesolithic diet of two people in Scotland following a strict wild food-only diet for a year, and a follow-up formal study of 24 participants eating wild food over a 1-month and a 3-month period, with their gut microbiomes measured against a control group and a blood panel at start and end points. Results showed overall improvements in most measures of modern disease, including obesity, blood pressure, blood sugar control, and inflammation, as well as increased gut microbiome diversity. The group average overall ZOE microbiome score was 52 (control 51) at the start of the ‘wildbiome’ diet. At the end of 3 months, the group microbiome score was 65 (control 52), a change of +13 (control +1).