Various scientists and philosophers have heavily criticized what they see as problematic forms of ‘nutritional reductionism’ or ‘nutritionism’ whereby studying food–health interactions at the level of isolated food components produces largely misguided science and misleading interpretations. However, the exact target of these diverse criticisms remains elusive, and its implications are overstated, which may hinder scientific understanding. To better identify the types of flaws supposedly hindering reductionist research, we disentangle three types of reductionist claims to better determine what the debate is (...) about and to propose ways to move it forward. We then present a qualified defence of the reductionist programme that hinges on the ability to identify nutritional causes that make a difference, which we illustrate through central examples in the history of nutrition. This defence is taken further by using insights from the philosophy of mechanisms to analyse how the field of nutritional ecology offers a synthetic framework to explain, generate, and test predictions about nutrient–organism interactions, which is premised on the biological mechanisms of nutrient-specific appetite regulation. The result, which we call ‘synthetic reductionism’, avoids many, though perhaps not all, of the challenges raised by anti-reductionists, and also highlights the potential of reductionism to identify nutritional difference makers. (shrink)

A widespread perception is that carnivores are limited by the amount of prey that can be captured rather than their nutritional quality, and thus have no need to regulate macronutrient balance. Contrary to this view, recent laboratory studies show macronutrient‐specific food selection by both invertebrate and vertebrate predators, and in some cases also associated performance benefits. The question thus arises of whether wild predators might likewise feed selectively according to the macronutrient content of prey. Here we review laboratory studies demonstrating (...) the regulation of macronutrient intake by invertebrate and vertebrate predators, and address the question of whether this is likely to also occur in the wild. We conclude that it is highly likely that wild predators select prey or selectively feed on body parts according to their macronutrient composition, a possibility that could have significant implications for ecological and foraging theory, as well as applied wildlife conservation and management. (shrink)