The most efficient strategy to adopt for any exercise is a gradual build -up over several weeks. All the body systems need to be brought to a state of fitness gradually, not just the muscles. There is no need to increase protein intake to build muscle, most of the protein that you eat will simply be destroyed, putting an extra load on the kidneys.
Keep three meals a day based on wholemeal or whole grain starch and fruit (without added sugar) and vegetables (without too much added fats) and a single portion rich in protein with one meal a day.
If you find your appetite increasing with the extra exercise, add to the starch in your meals, not the protein and not extra fat. If you are to engage in prolonged heavy exercise, such as hard manual labour for more than 8 hours each day, you may even require four large starch based meals a day. But do resist the temptation to cover the starch with fat or sugar.
For intensive occasional exercise the body is dependent on mobilising reserves already in place rather than deriving them from food immediately before or during the exercise. Training over several weeks ensures that this mobilisation of reserves takes place efficiently and is less likely to cause the highs and lows of blood sugar that result from high sugar and fat diets.
Any food remaining in the stomach will reduce the body's capacity to participate in intensive exercise. Do not eat a fatty meal any closer than 4 hours before vigorous exercise. A protein rich meal requires at least two hours for digestion before starting vigorous exercise and a starchy meal one hour.