The primary objective of pork production is to produce lean meat in a cost effective and sustainable manner. From a nutritional perspective, energy is perhaps the most critical nutrient, because it is the most expensive to provide in the diet. Energy is also an important driver of growth; achieving the full genetic potential for growth in the modern pig requires a clear definitive understanding of the pig’s energy response curve. Feeding the pigs lower energy programs may maximize net income. However, the results of individual phases within this experiment suggest that feeding higher energy diets up to 80 kg may be warranted, as this is the period when pigs would respond the most to the higher energy diets. Furthermore, the relative cost of high and low energy ingredients will dictate the optimum energy concentration. It is clear from this experiment, and from others conducted previously, that the response to dietary energy concentration is not easy to predict. If pigs are able to consume sufficient quantities of feed to achieve excellent growth on lower energy diets, then feeding higher energy diets is unlikely to be beneficial. However, if feed intake is low, then there may be a benefit to feeding higher energy diets, to increase daily energy intake and thus support faster growth. Nonetheless, we caution producers from assuming that increasing dietary energy will universally increase pig performance; experimental data does not support such an assumption.