These are important and exciting times for research on sustainable aquaculture. Advancing our understanding about the nutritional requirements of aquaculture species and improving feeds are critical to sustainable aquaculture. Important drivers of aquaculture nutrition research include: climate and environmental change; decreasing availability of traditional marine ingredients; increasing opportunities for new and more sustainable feed ingredients; inclusion of nutrition-based traits in selective breeding programs; and increasing awareness of meeting human nutritional needs. Nutritional physiology is a term often used to describe nutrition research that, arguably, makes more holistic consideration of aquaculture organisms and their environment. The environment is particularly relevant because all aquaculture animals are aquatic ectotherms and their energy expenditure is dependent on environmental temperature. The aim of this presentation is to overview research methods and approaches being used to better understand the nutritional physiology of lobster species with a focus on protein metabolism. The research approach integrates bioenergetics and protein-nitrogen flux to measure nutrient intake, biosynthesis, retention and waste to more closely examine different feed formulations. Energy substrate use (ESU) of protein, lipid and carbohydrate was calculated by combining respiration (oxygen) and excretion (carbon dioxide, nitrogen). Stable isotope incorporation revealed information about both ingredient use and biosynthesis. Combining these data types refined the approach for determining energy and macro-nutrient utilisation. Thus, adopting a nutritional physiology approach provides multiple layers of information to optimise feeds and support sustainable lobster aquaculture.