The last nomadic peoples of the world are facing strong governmental incentives to renounce their foraging lifestyle. Nevertheless, the shift to a sedentary way of life and the adoption of agriculture do not always result in the promised improvement in diet and health conditions.We compared the dietary regime and nutritional status of three groups of former hunter-gatherers, the Punan of Borneo. All three groups adopted extensive upland rice cultivation almost 6 decades ago, but each has some degree of dependence on agriculture versus forest resources, which varies along a gradient of accessibility of urban facilities.The diet of three distinct Punan groups living in the dipterocarp forest of East Kalimantan was assessed both qualitatively and quantitatively and analyzed in relation to the seasonality of resources and human activities. The physical fitness of the Punan was also estimated from repeated anthropometric measurements.The more remote the Punan community was from urban facilities, the more diversified was the diet and the better were its nutritional status and physical fitness. The contribution of forest resources to the dietary regime also decreased with urban proximity. However, the higher dependency on agriculture is not the proximate cause of the deterioration in diet and physical fitness, which is rather due to the transition from the nomadic to the settled way of life.The brutal shift in lifestyle among the Punan of Borneo has profoundly affected the integrity of these societies and impacted their social, cultural, symbolic, and political features. In the long run, this may compromise their health status and ecological success.