Fat and carbohydrate for exercise

PURPOSE OF REVIEW: To examine the results of new investigations that look at the efficacy of nutrient/training strategies on metabolism and athletic performance. RECENT FINDINGS: 'Dietary periodization' involves the manipulation of macronutrient intake in association with changes in physical training. Such interventions have a major effect on altering patterns of fuel utilization during exercise; however, they often fail to enhance performance capacity. In contrast, the ingestion of a combination of different types of carbohydrate during exercise results in high rates of muscle glucose oxidation (1.5 g/min) and can improve intense, short-duration (~60 min), and prolonged (>90 min) submaximal steady-state exercise, either by metabolic or neural mechanisms. SUMMARY: Further investigation into the responses of specific nutrient/training strategies on metabolic and cellular signaling pathways is warranted to determine the underlying mechanisms by which such interventions exert their effect. Such studies, however, should be coupled with investigations that assess the outcomes of these responses on the 'real life' training adaptations in athletes.