With the athlete I coach, I promote what I call the “Right Fuel, Right Time” approach to nutrition for endurance training, as discussed in blogs and on our courses. By "Right Fuel, Right Time," I mean advocating for the timely management and adaptation of nutrition, particularly carbohydrate intake, according to training demands. These objectives may aim to maximize acute performance within the session or facilitate high rates of fat oxidation.

In the literature, we come across the term "Periodised carbohydrate intake," which is an approach that follows a very similar principle and is seeing increasing research interest (1, 3).

The rationale for this approach is that adequate carbohydrate should be consumed to support the quality of training sessions. However, we should avoid over-consuming carbohydrates on easier, less demanding days, as this may blunt the signals that lead to positive adaptive responses (2). Carbohydrates and fats are the body’s primary fuels....