Here's what 3 of Wall Street's fiercest competitors eat to stay in top shape

Because of how early the workouts are (some start at 5 a.m.), Howell doesn't always eat beforehand. 'I either train fasted, or eat something light, like applesauce, to get the wheels turning,' he told Business Insider.

After the workout, Howell's appetite calls for a more complete meal. 'I eat three to four eggs with multigrain toast and a recovery drink, such as a protein shake,' he said.

Throughout his training, Howell's overall diet is high in fat and protein, and he includes a moderate amount of complex carbohydrates.

During training season, Santaniello follows what she calls the 'P-F-C rule.'

'(I eat a) protein-fat-carb at each meal and snack,' she said. 'Before a workout, I usually like to fuel up on a handful of nuts and a piece of fruit, or an RXBar -- apple cinnamon is my favourite.'

Post-workout, her meal includes half of a sweet potato and a plant-based protein shake with almond milk and half of a banana or frozen acai berries.

For Fincher, a protein shake is always in order, both before and after a workout session.

'For me, having a protein shake an hour before the session does the trick,' he said. His smoothies consist of whey protein, bananas, blueberries, chia seeds, and coconut milk.

After a session: 'I follow up it with a large breakfast when possible.' His go-to is a ham and veggie omelet made with three eggs and a side of fruit.